bluuebunny/crossref_metadata_2025 huggingface dataset:
Serial dependence in a superposition of renewal processes
Authors: Linebarger Darel , Johnson Don
Published: October 2005

Superposition of point processes has often been suggested [I. Gath, Math. Biosci. 22, 211–222 (1974); C. E. Molnar and R. R. Pfeiffer, Proc. IEEE 56, 993–1004 (1968)] as a model for neural discharge patterns due to its intuitive appeal (input spike trains are simply merged and then retransmitted), and the tendency for successive interspike intervals in the superposition to be negatively correlated. Discharge patterns in the lateral superior olive (LSO) of the cat often display such negative serial dependence. The properties of the superposition of two identical renewal processes are examined in relation to the properties of its components. Components with increasing intensity functions are proven to yield a superposition process having negative serial dependence. However, the imposition of a dead time on a superposition process is shown to remove much of the serial dependence. For this reason, it is suggested that superposition of renewal processes is not a good model for discharge patterns having both a dead time and significant serial dependence, such as LSO discharge patterns.
A π shift in the spatial distribution of response phases of auditory-nerve fibers
Authors: Ruggero Mario A. , Rich Nola C.
Published: October 2005

Chinchilla auditory-nerve fibers respond to low-frequency tones (⩽100 Hz) at near-threshold levels with phases that are strongly dependent on characteristic frequency (CF) or site of innervation [M. A. Ruggero and N. C. Rich, J. Acoust. Soc. Am. 73, 2096–2108 (1983)]. We have extended these findings for stimulus frequencies between 100 and 1000 Hz. For stimulus frequencies above 100 Hz, response phases lag steadily so that at about 1000-Hz basal fibers are excited with a lag of nearly 240° relative to frequencies below 100 Hz. The same pattern of phase lag with frequency holds for fibers with CFs below 2 kHz (but greater than twice stimulus frequency) except that their responses are nearly 180° out-of-phase relative to high-CF fibers. At all frequencies the phase transition occurs at stimulus levels (40–80 dB SPL) substantially lower than those required to elicit “peak splitting.” For CFs lower than twice stimulus frequency phase lag is inversely related to CF with slopes of about 400°/octave CF, qualitatively in agreement with mechanical cochlear travel times. Because it is unlikely that a mechanical discontinuity exists in the basilar membrane region corresponding to CFs of 2–4 kHz, it would seem that the π shift in neuronal response phases is due to a transition between two modes of excitation at the hair cell or synaptic level. [Work supported by NIH and NSF.]
Long-term adaptation in afferent neurones from the normal and pathological cochlea
Authors: Harrison Robert V.
Published: October 2005

During continuous steady-state acoustical stimulation, the rate of discharge of afferent cochlear neurones reduces rapidly at first, then more slowly. Numerous studies have been made on short-term adaptation [e.g., R. L. Smith, J. Acoust. Soc. Am. 65, 166–178 (1979)] but few have characterized adaptation for periods longer than 1 s or in animals with cochlear pathology. The discharge adaptation during 30 s of continuous acoustic stimulation has been investigated in normal cochlear fibers (N = 75) in the guinea pig, and compared with that in fibers (N = 85) from kanamycin treated cochleas. As a function of stimulus level, long-term adaptation rate increases for stimuli of increasing intensity, reaching a value of 0.4%–0.5% decrease in rate per second for stimuli 30-dB suprathreshold. In some normal fibers, rate of adaptation is further increased at high stimulus levels (cf. 60 dB above threshold) resulting in long-term discharge rate versus intensity functions that are nonmonotonic. In kanamycin damaged cochleas (400 mg/kg/day for 10 days producing more than 50% loss of outer hair cells), fibers show no significant difference in discharge adaptation compared with the normal cochlea. This implies that synaptic function is not impaired. This study confirms some indirect measures of cochlear adaptation [M. P. Gorga and P. J. Abbas, J. Acoust. Soc. Am. 70, 1310–1321 (1981)]. The results are consistent with clinical observations that loudness adaptation (tone decay) is associated more with retrocochlear lesions than with pure cochlear lesions.
Morphological and electrophysiological study of experimental endolymphatic hydrops in guinea pig
Authors: Smoorenburg G. F. , Albers F. W. J. , van Deelen G. W. , Ruding P. R. J. W. , Veldman J. E.
Published: October 2005

Endolymphatic hydrops was experimentally induced in guinea pig ears by obliteration of the endolymphatic sac. One, two, four, and eight months after obliteration the animals were sacrificed for histological examination. Immediately before sacrificing the animal, compound action potentials (AP) and summating potentials (SP) were measured from both, the hydropic and the control ear. After one month, a distention of Reissner's membrane (hydrops) was found which reached the bony wall of scala vestibuli in 50% of the ears. After eight months the majority of the guinea pig ears showed extensive hydrops. In addition, we found thin connections between Reissner's membrane (RM) and the bony wall, ruptures of RM, thickening of RM and defects in the mesothelial cells, edema followed by atrophy of the stria vascularis, and loss of spiral ganglion cells and nerve fibers. The outer hair cells, followed by the inner hair cells, showed progressive degeneration starting at the apical end of the cochlea. One month after obliteration the AP threshold for the hydropic ear did not differ from the threshold for the control ear. Two months after obliteration small AP-threshold shifts were found which increased up to 40 dB after eight months. For 2- and 4-kHz stimuli an enhanced negative SP was found after one month when the extracochlear electrode was placed near the apex. After four and eight months the enhanced negative SP turned into a reduced SP. The enhanced SP is ascribed to the hydrops provoking a deviant resting position of the basilar membrane. The decrease in AP and SP amplitude two and more months after obliteration is ascribed to the loss of hair cells and spiral ganglion cells.
Is threshold microstructure a manifestation of tone-on-tone masking?
Authors: Long Glenis R. , Tubis Arnold , Jones Kenneth
Published: October 2005

Dips in the masked behavioral thresholds for near-threshold maskers and fprobe≈fmasker [see e.g. R. L. Wegel and C. E. Lane, Phys. Rev. 23, 266–285 (1924); L. L. M. Vogten, J. Acoust. Soc. Am. 63, 1509–1519 (1978)] bear a striking resemblance to the dips in the microstructure of quiet thresholds. In combination with the high correlation of the microstructure dips with spontaneous and/or evoked oto-acoustic emissions, this suggests that threshold microstructure may, at least in part, be due to simultaneous masking of an external tone by a cochlear generated tone. In order to further explore this possibility we have compared the natural microstructures of quiet thresholds with simulated microstructures induced by near-threshold tonal and narrow-band-noise external maskers. An attempt has been made to understand the similarities and differences between the two situations in terms of cochlear model simulations. We have also systematically controlled the relative phases of the masker and probe so as to simulate the entrainment of spontaneous otoacoustic emissions by external tones. [Work supported by NIH.]
The NST in noise
Authors: Danhauer J. , Lucks L. , Doyle P. , Burke J.
Published: October 2005

The effects of white noise, multitalker noise, and amplitude-modulated white noise competitors on 20 young adult normal-hearing listeners' responses to the nonsense syllable test (NST) were evaluated. Responses were also compared to the NU-6 test presented in the same conditions. Stimuli were presented via earphones at a 0-dB signal-to-noise ratio. Subjects' verbal responses were word scored and analyzed statistically. Responses were always poorer on NST than on the NU-6 regardless of noise type; multitalker noise was easiest followed by white noise and amplitude-modulated white noise. These and earlier results indicate that the NST is difficult and sensitive enough to be presented in quiet and that testing in noise may not be warranted.
Discrimination of synthesized syllables, differing in VOT, by normally hearing children and adults
Authors: Elliott Lois L. , Busse Lu Ann , Partridge Randy , DeGraaff Robert , Rupert Jennifer
Published: October 2005

Adaptive test procedures were employed in a field study to determine just-noticeable differences relative to each endpoint of an eight-item, /ba/pa/ continuum of five-formant, synthesized syllables that differed in 5-ms VOT steps. Difference limens for young adults were smaller than for 8–10 year-old children, for whom jnds, in turn, were smaller than for 6–7 year-old children. Difference limens at the /pa/ end of the continuum were larger than those for /ba/, for each age level. These age-related differences in VOT discrimination, in the presence of essentially 100% correct performance for all Ss on a clinical test of word discrimination, resemble previously reported age-related differences in discrimination of the place of articulation feature [L. L. Elliott et al., J. Acoust. Soc. Am. 70, 669–667 (1981)]. Performance of normally hearing, learning-disabled children will also be discussed. [Work supported, in part, by NINCDS.]
Linear amplification for low-frequency hearing loss
Authors: Collins M. J. , Schum D. , Yanda J. L. , Fryauf H.
Published: October 2005

Individuals with low-frequency hearing loss and a rising audiometric contour often reject amplification with low-frequency emphasis. One possible explanation is that apical function is limited to the extent that primarily basal fibers are responding to low-frequency signals, leading to marked intraspeech masking. In the extreme case, the intelligibility of speech may vary inversely with the relative amount of gain provided in the low frequencies versus the higher frequencies. In order to test that hypothesis, three amplification schemes were evaluated on a group of hearing-impaired persona with low-frequency hearing loss. Low-pass (LP) functional gain was provided only in the region of greatest hearing loss, high-pass (HP) functional gain was provided on the rising portion of the audiogram, and broadband (BB) functional gain was provided equally across all frequencies. Subjective preference and speech recognition in noise were used to rank order the three schemes for each subject. The usefulness of low-frequency gain varied across subjects. In some cases it was possible to relate the ranking of amplification schemes to the degree to which high-frequency fibers carry low-frequency information as evidenced by psychophysical masking functions. These results suggest that traditional approaches to selecting amplification may be inappropriate for individuals with audiograms indicating low-frequency hearing loss. [Work supported by DRF.]
Color display of vowel spectra as a speech training aid for the deaf
Authors: Zahorian Stephen A. , Jagharghi Amir J.
Published: October 2005

In this paper, the development and use of a vowel to color converter as a speech training aid for the deaf will be discussed. The vowel spectra are encoded in terms of six spectral shape factors called spectral principal components. The basis vectors used to compute the principal-components parameters have been optimized for use with the 16 bandpass filters which are the first processing stage of the speech training aid. Measurements based on vowels spoken in an /hVd/ context illustrate the clustering of vowel spectra in this parameter space. A linear transformation is used to convert the spectral parameters to control the red, green, and blue inputs of a color CRT display. The transformation is designed to maximize the distance between the three widely separated vowels /a/, /u/, and /i/. A “flow-mode” display is used. The results of preliminary training experiments to aid in vowel articulation will be presented. [Work supported by the Whitaker Foundation.]
Preliminary evaluation of a synthetic Tadoma system
Authors: Leotta Daniel F. , Rabinowitz William M. , Reed Charlotte M. , Durlach Nathaniel I. , Braida Louis D.
Published: October 2005

At the 105th ASA meeting we presented results of our research on the Tadoma method of tactile speech reception and described our ongoing development of a “synthetic Tadoma system” for use as a research tool in studying transformations of Tadoma [Reed et al., J. Acoust. Soc. Am. Suppl. 1 73, S26 (1983)]. In the synthetic Tadoma system, signals recorded from a talker's face are used to control an artificial mechanical face. Preliminary evaluation of the system has involved roving ABX discrimination tests among sets of 15 vowels in CVC contexts and among sets of 24 consonants in CV contexts. Two naive adult subjects, with simulated deafness and blindness, have been tested. Average results for vowel discrimination (68%) were equal to those obtained in a comparable study of natural Tadoma [Reed et al., J. Speech Hear. Res. 21, 625–637 (1978)]. Results for consonant discrimination were lower for the synthetic system (68% vs 78%), but were improved (to 74%) following certain modifications to the system. [Work supported by NSF.]
Classroom evaluation of a wearable 16-channel electrotactile sensory aid for the deaf
Authors: Saunders Frank A. , Franklin Barbara
Published: October 2005

Preliminary data will be presented from field evaluations of a wearable 16-channel electrotactile sensory aid for the deaf. Studies were conducted with six profoundly deaf elementary school children, participating in a special program for the hearing impaired at the Jackson Hearing Center, Palo Alto Unified School District, California. Videotaped assessments of the children's speech reception and speech production were taken prior to training and at three-month intervals thereafter. Conventional training procedures were utilized, oriented toward individually targeted speech defects for each child. The assessment procedure was conducted in three modes: (a) aided residual hearing alone, (b) aided hearing plus lipreading cues, (c) aided hearing plus lipreading plus tactile cues from the sensory aid. [Work supported by SBIR/NIH.]
A three-phase psychoacoustic assessment of learning disabled subjects
Authors: DeFosse Carlton O.
Published: October 2005

A three-phase assessment paradigm was implemented to evaluate areas of auditory and visual perceptual integration and processing by a heterogeneous group of 35 learning disabled subjects ranging in age from 4 to 37 years. Phase I involved testing peripheral auditory acuity, phase II tested central auditory processing, and phase III evaluated cognitive integration of auditory and visual sensory information. Subtest analysis was performed to identify the test material most sensitive to identification of perceptual impairment. Several diagnostic profiles emerged from the test data, and will be discussed in regard to relevance in selecting the assessment battery most appropriate for testing auditory and visual sensory perception of the learning disabled.
Where have all the segments gone?
Authors: Parker Frank , Walsh Thomas
Published: October 2005

Two questions arising from the ongoing debate between “physicalists” and “mentalists,” with Carol Fowler and Robert Hammarberg, respectively, representing the protagonists, are discussed in this paper. (1) Are coarticulation and phonological assimilation distinct processes? (2) Are phones and phonological segments physically definable entities? We conclude that the first question is still open, and we outline the type of evidence that would bear on it. However, we suggest that the opposition between coarticulation and phonological assimilation is best recast as an opposition between effects with “mental cause” and those with “physical cause.” Moreover, we argue that the burden of proof falls on those who want to argue for a distinct class of assimilation which has “physical cause.” We find that the second question falls within the domain of theory evaluation. We argue that Hammarberg's view (segments are solely mental) is preferable to Fowler's (segments are both mental and physical) on three counts. (1) Historically, the “mentalist” view in linguistics supplanted the “physicalist” view because the latter could not account for all relevant observations. (2) The nonphysical nature of linguistic entities in general would lead us to expect a priori the nonphysical nature of segments. (3) The assumption of physical segments within the articulatory mechanism does not resolve any pressing problem in linguistics or speech science. [Work supported in part by NIH.]
Comparative EMG investigation of French and English disyllables
Authors: Gentil Michele , Harris Katherine S. , Horiguchi Satoshi , Honda Kiyoshi
Published: October 2005

The activity pattern of various muscles was examined to compare the production of French and American English disyllables. Eiectromyographic signals were recorded from seven muscles, five associated with tongue movement, and two with lip and jaw movement. One speaker of each language produced disyllables in the form /pVCap/, where V = /i,a,u/ and C = /p,t,s/, at two speaking rates. Results will be discussed in terms of vowel coarticulation effects on consonants, both within and between languages.
Design and construction of an alternating magnetic field system for transducing articulatory movements in the midsagittal plane
Authors: Perkell J. S. , Cohen M. H.
Published: October 2005

A system for tracking multiple articulatory movements in the midsagittal plane has been designed and prototyped. The system uses alternating magnetic fields generated by two transmitter coils which are mounted in a magnetically transparent assembly that fits on the subject's head. Receiver transducers consist of small (4 × 4 × 2 mm) biaxial inductors which are attached to articulatory structures and have fine lead wires that are connected to demodulating circuits. The biaxial transducer design provides measurements that are independent of transducer tilt [J. S. Perkell, J. Acoust. Soc. Am. Suppl. 1 71, S32 (1982)]. Movements of as many as seven points inside and outside the vocal tract can be tracked, with two additional fixed points for use as a maxillary frame of reference. The measurement area is 150 × 150 mm, allowing for coverage from the rear wall of the pharynx to the lips and the bridge of the nose to the base of the tongue. Output voltages are low-pass filtered and digitized. Algorithms have been developed for conversion of digitized voltages to Cartesian coordinates. Output can be displayed as X and Y coordinates versus time or X versus Y trajectories. [Work supported by NIH Grant NS04332.]
Coordination of lingual and laryngeal gestures in speech
Authors: Ostry David J. , Munhall Kevin G.
Published: October 2005

Although it is clear that there is extensive cooperation among the articulators in the production of speech, the various ways that articulatory movements can be coupled have yet to be explored in detail. In this paper, we present preliminary findings on the nature of the tongue-vocal fold linkage in the production of repetitive speechlike sounds. Subjects produced the utterance /kakak/ at both normal and fast speech rates with either the first or the second vowel stressed. The lowering movement of the tongue dorsum and the abduction and adduction gestures of the vocal folds were monitored simultaneously by using a computerized ultrasound system. The kinematic patterns of tongue and vocal fold movement were assessed in terms of linkages between movement amplitudes, durations, maximum velocities, and movement trajectories. Both cooperative and compensatory patterns were examined. In addition, phase relationships between the tongue and vocal folds were evaluated as a function of differences in rate and stress. The discussion focuses on the bases of cooperation in these interarticulator movements.
Evaluation of foreign accent using synthetic speech
Authors: Rekart Deborah , Hoffman Paul , Daniloff Raymond
Published: October 2005

A meaningful sentence loaded with appropriate phonemic and syllabic forms was synthesized as a “standard” stimulus, and 15 “accented” versions of the sentence were made by manipulating the following Spanish cues singly and in combination: (1) VOT for syllable-initial voiceless stops, (2) vowel duration, (3) F1 and F2 for full vowels, and (4) F1 and F2 plus duration for reduced vowels. Two tapes were prepared on which the 15 accented stimulus sentences were each paired with the standard sentence in two randomized sequences. Ten English speakers rated how different the accented sentence was from the standard sentence on a ten-point scale. Statistical analysis revealed a significant difference in perceived accentedness as a function of the number of cues present and in particular, differences elicited by a shift in F1 and F2 for full vowels.
The automatic vowel of Cr clusters
Authors: Hernández Mariscela Amador
Published: October 2005

Two phenomena are reported in the phonemic descriptions of various languages: Some languages tend to create /Cr/ or /rC/ clusters by reducing an intervening unstressed vowel. Other languages tend to dissolve such clusters by lengthening the vocalic transition that occurs between the two segments, this vocalic transition being originally automatic, i.e., due to articulatory and/or aerodynamic constraints. Oscillograms were made to measure the duration of such automatic vowels in stressed and unstressed syllables in Spanish. Pressure records were also made to show the variation in air-flow during articulation. Perception tests were then performed to assess how clusters form and dissolve when duration of the automatic vowel is systematically shortened or lengthened. Edited utterances were played to native speakers of Spanish who were asked to judge whether they heard a version with a cluster or with no cluster. The likelihood of a stimulus being perceived as a cluster was inversely proportional to the duration of the automatic vowel. However, the perceived cluster was not so readily dissolved before following full vowels /a/ or /o/.
From sound to meaning: A lexical access model
Authors: Fromkin Victoria A.
Published: October 2005

A model of the lexicon and how it is accessed in speech production and perception is proposed using data from both normal and aphasic subjects. Evidence will be presented from a case study of an acquired “surface dyslexic” to show that there is no direct semantic interpretation of the acoustic signal but that it must first be transformed into an abstract phonological representation before meaning is assigned. The interconnecting pathways between phonological, orthographic, and semantic representations in the lexicon of a normal speaker and a language disordered speaker are discussed, as are the various types of processing rules in reading, writing, speaking, and understanding.
Effects of subcategorical mismatches on shadowing
Authors: Whalen D. H.
Published: October 2005

When the fricative noise of a fricative-vowel syllable is replaced by a noise from a different vocalic context, listeners experience delays in identifying both the fricative and the vowel [D. H. Whalen, Percep. Psychophys. 35, 49–64 (1984)]. Similar delays occur in making a lexical decision on words containing mismatches [D. H. Whalen, Haskins Laboratories Status Report SR-73, 1–15 (1983)], though the delays were not significant for nonwords. In the current experiment, noises and vowels within words and nonwords were cross-spliced, and subjects were instructed to repeat (“shadow”) each stimulus as rapidly as possible. Preliminary results indicate that subjects experience delays in shadowing both words and nonwords with mismatched information. Further support for this result would provide evidence against both a prototype model (e.g., the logogen model) and a linearly ordered model (e.g., the cohort model) of lexical access. Instead, word perception would be viewed as simultaneous with phonetic perception: Although word decisions can be made with incomplete information, the perceptual system deals with all information which is present. [Work supported by NIH Grant HD-01994.]
A feature-based time domain pitch tracker
Authors: Phillips Michael S.
Published: October 2005

A pitch tracking algorithm was designed that uses perceptually motivated features to identify the first peak of each pitch period in the speech waveform during voiced portions of speech. The feature measurement algorithms were designed to capture all of the information that a person uses to identify pitch marks when looking at a waveform display. A multi-variate classifier makes decisions about the location of pitch marks based on the values of the feature measurements. This classifier was designed using Classgraph—a program that allows the user to examine hand-labeled data and make decision boundaries in the multidimensional feature space. Performance was evaluated by comparing pitch marks generated by the algorithm with hand-labeled pitch marks on a database of speakers each saying a different sentence. Each sentence was hand-labeled by two people. The agreement among labelers was within 1% of the agreement between each labeler and the output of the algorithm. [Supported by NSF and DARAP.]
Reverberation time in physically small rooms
Authors: Davis Don , Patronis E. T.
Published: October 2005

Physically small rooms are often erroneously analyzed and measured according to the classical statistical acoustical equations and techniques. Evidence is presented herein to support the position that a truly diffuse reverberant field does not exist in such spaces at a level above that of the ambient noise.
Isolating music and mechanical equipment sound sources with gypsum board partition systems
Authors: Roller H. Stanley
Published: October 2005

The 100-Hz low-frequency limit for sound transmission loss measurements and the STC rating system have seriously limited the development of a vocabulary of practical lightweight constructions which can effectively isolate music and mechanical equipment sound sources. This paper discusses the results of recent research on gypsum board partition systems which include sound transmission loss measurements down to 50 Hz and the evaluation of a number of design factors such as balanced and unbalanced constructions, panel damping, cavity resonances, and cavity insulation. Measurements made at 50-, 63-, and 80-Hz one-third octave bands are in good agreement with calculated TL at these frequencies. These data, plus calculated TL at 31 and 40 Hz, are used to further evaluate the proposed MTC (music and mechanical equipment transmission class) rating system which is based on 125- to 5000-Hz data.
Review of some approaches to architectural-acoustic design of sound recording facilities in the U.S. S. R.
Authors: Kacherovich Gregory A.
Published: October 2005

Rooms are classified for their purpose in relation to acoustics, based on the authors's experience in architectural-acoustic design and consulting in the U.S. S. R. for over 20 years. General acoustic requirements are set for each group of rooms. Auditoria are classified depending on the sound source origin. Special attention is brought to sound recording studios and related spaces used for radio, television, and motion picture facilities. General acoustic criteria, general approach in design, selection of size, shape, and materials are discussed for different groups of rooms including motion picture and television stages, music and speech recording studios, re-recording studios, control rooms, etc. Music recording studios are considered to be of two major types depending on the use of distant and close pickup microphones. Several multi-purpose studios were designed and built in the 1970's providing the necessary acoustic environment for music and speech recording as well as for re-recording purposes. Systems for variable acoustics were developed providing a wide range of variability.
Sound in the early universe
Authors: Vishniac Ethan T.
Published: October 2005

The standard cosmological model is based on the approximation that the universe is homogeneous and isotropic. The overwhelming success that this model has enjoyed is based on its ability to predict the primordial abundance of elements and the isotropy of the microwave background. However, the universe itself is not homogeneous. Any realistic model must include the perturbations from homogeneity that evolved into galaxies and galaxy clusters. Perturbations on these scales behaved like sound waves at sufficiently early times when the gas in the universe was almost completely ionized. In this talk I will review the work done on the linear and nonlinear evolution of these sound waves. The isotropy of the microwave background places firm limits on the amplitude of the sound waves at the epoch of recombination. As a result we are able to rule out the hypothesis that the universe consists entirely of radiation and ordinary matter.
Shock waves in astrophysics
Authors: Bertschinger Edmund
Published: October 2005

Gravitational forces acting on a large scale often generate supersonic velocities in cosmic gas leading to shock waves. Astrophysical shock waves range in size from the earth's bow syhock in the solar wind to interstellar shock waves generated by supernova explosions, and perhaps to galaxy-size explosions in the early universe. Shock waves are important to astronomers and astrophysicists for a variety of reasons. Shocked gas emits radiation which serves as a useful diagnostic of the composition and state of the gas. Radiative shock waves, because they can greatly increase the gas density and hence gravitational binding energy, are also important in enhancing star formation. A review will be given of the causes, occurrence, and significance of astrophysical shock waves. The theoretical, observational, and computational methods used to study them will also be discussed.
Coherent vortical features in a turbulent two-dimensional flow and the Great Red Spot of Jupiter
Authors: Marcus Philip S.
Published: October 2005

We present the results of an initial-valve study of a nearly inviscid flow in a low aspect ratio, rapidly rotating, cylindrical annulus with a free upper surface and with a sloping bottom surface. In the limit of very rapid rotation, the equations and solutions of this flow are the same as those of a planetary atmosphere whose density decreases exponentially with height. We have found numerically that for a wide range of initial conditions the flow settles into a statistically steady state that consists of an isolated coherent spot of vorticity superposed on a turbulent zonal (statistically axisymmetric) flow whose time-averaged vorticity is linear in radius (or linear in latitude of a planetary atmosphere). The strength and sign of the vorticity in the zonal flow and in the spot, the shape and location of the spot, and the interaction of the spot with other features are quantitatively similar to the properties of the Red Spot of Jupiter and the zonal wind in which it is located. The time-averaged features of the zone and the spot are surprisingly insensitive to a number of different types of boundary conditions. We present examples of solutions where two or more spots (present as intial conditions) merge into one spot, and where a spot with the wrong sign of vorticity breaks up and reforms rotating with the correct sign. An analytic model is developed based on the numerical results that shows that under some conditions a spot must necessarily form, and that two or more spots must merge into a single spot. The model's predictions of the size, shape, strength, and location of the spot are in good agreement with the numerical results. We conclude by discussing the feasibility of reproducing this flow (i.e., a coherent spot in a turbulent background) in the laboratory.
Some physical insights and mathematical models for the sound reception by the human pinna
Authors: Kuhn George F.
Published: October 2005

The frequency response, directional gain, standing wave ratios, and pressure distributions for models of the human pinna, composed of regular geometrical sections, have been determined analytically to approximately 12 kHz. These analytical models yield new, significant insights into the physics of sound collection by the pinna, its efficiency, and the effect of the pinna's geometrical details on the frequency response and the directivity. Some simplifying approximations of the mathematical formulations yield useful rules about the relationships between the pinna geometry and the gain function as well as the spatial and spectral locations of pressure-peaks and pressure-nulls. [Work supported by NIH/NINCDS.]
Acoustics of ear canal measurement of eardrum SPL
Authors: Gilman Samuel , Dirks Donald
Published: October 2005

This paper reports on a study to determine the effects of standing acoustic waves on the accuracy of ear canal determination of eardrum SPL. The study was conducted in three parts: (1) A theoretical analysis of standing waves of sound pressure in a lossless transmission line having the geometry of the average ear canal with terminations corresponding to the extremes in normal eardrum impedance, (2) actual probe measurements on ANSI S3.25-1979 ear simulators, modified so that ear canal length and eardrum impedance could be varied, (3) probe determination of eardrum SPL on real ears. Results from simulator and real ear measurements agree with the theoretical determinations obtained from the standing wave study. Theoretical and actual standing wave ratios agree with published real ear data [E.A.G. Shaw, “Transformation of sound pressure level from the free field to the eardrum in the horizontal plane,” J. Acoust. Soc. Am. 56, 1848–1861 (1974)].
Acoustic pressure distributions in cadaver ear canals
Authors: Kuhn George F.
Published: October 2005

The plane wave acoustic pressure distributions in cadaver ear canals have been calculated up to 20 kHz, taking into account the geometry of the ear canals. Also, the pressure distributions across the eardrums as well as the average—and central—pressure (at the umbo) have been calculated. The results indicate that at high frequencies the spatially averaged pressure across the eardrum, the central pressure (at the umbo), and the maximum pressure in the standing wave in a uniform extension of the ear canal differ little from each other. Since the pressure distribution across the eardrum varies greatly in amplitude and phase, a rotational movement about the umbo or central portion of the eardrum is shown to be a potential mechanism of transduction of sound to the middle ear. [This research is sponsored by NIH/NINCDS.]
A model for changes in middle-ear transmission caused by stapedius-muscle contractions
Authors: Pang Xiao-Dong , Peake William T.
Published: October 2005

We have observed in cats that when the stapedius muscle contracts, the stapes moves by as much as 60 μm, while the incus and malleus are not detectably displaced (< 1 μm). This observation provides physiological support for the hypothesis that stapedius contractions change only the impedance of the stapes. A network model has been developed to test this hypothesis. The middle ear is represented as a linear two-port network that is loaded by the impedance of the stapes and cochlea. A quantitative description of the two-port is derived from measurements of (a) acoustic input impedance (with and without load), (b) impedance of the stapes and cochlea, and (c) middle-ear transmission. With our measurements of changes in middle-ear transmission (for acoustic inputs ranging from 0.1 to 10 kHz) generated by stapedius contractions, this model is used to compute the changes in stapes impedance necessary to produce the measured changes in transmission (up to 30 dB). Results indicate the following. (1) The altered stapes impedance is representable by passive elements as its real part is positive. (2) As the magnitude of the stapes impedance increases with stronger muscle contractions both real and imaginary parts of the impedance change. (3) Changes in the stapes admittance are approximately proportional to changes in the transmission. (4) Changes in the middle-ear input impedance predicted by the model are compatible with measurements. Thus, the results support the hypothesis. [Work supported by NIH.]
Correlated changes in otoacoustic emissions and threshold microstructure during aspirin consumption
Authors: Long Glenis R. , Tubis Arnold , Jones Kenneth
Published: October 2005

The discovery that aspirin consumption can abolish spontaneous otoacoustic emissions [D. McFadden and H. S. Plattsmeir, J. Acoust. Soc. Am. 76, 443–448 (1984)] provides a technique for further exploring the relation between otoacoustic emissions (spontaneous and evoked) and psychoacoustic threshold microstructure. Spontaneous emissions, delayed evoked emissions, synchronous evoked emissions, and threshold microstructure were monitored before, during, and after consumption of 3.9 g of aspirin per day (three 325-mg tablets every 6 h). The changes in spontaneous emissions replicate the findings of McFadden and Plattsmeir. Evoked emissions and threshold microstructure were also reduced by aspirin consumption but persisted longer and recovered sooner. In most instances the initial change in threshold microstructure was a reduction of threshold maxima with threshold minima remaining relatively constant. Further aspirin consumption elevated all thresholds to a level slightly above threshold maxima in the pre-aspirin measures. [Work supported by NIH.]
Sensitivity to pressure in the cochlea and the electromodel
Authors: Offutt George C.
Published: October 2005

Stimuli were presented simultaneously to the chinchilla cochlea through the external meatus and the scala tympani so that displacements of the basilar membrane were controlled by dual pressure waves. Changes in the phase relationships of these pressure waves controlled the CM amplitude but often had little influence on the compound action potential. The N1 amplitude was apparently a function of the summed energy and was often independent of the phase difference between the two pressure waves. Thus, the mechanical displacements of the basilar membrane may not be the only source of energy for hair cell transduction in the cochlea. This requires a rethinking of the entire field of auditory research. It is possible that interpretations of all auditory research have been based upon a false assumption, and the inner hair cells (IHC) are primarily sensitive to electrical potentials. The tectorial membrane may be piezoelectric and perform the initial transduction of energy in the pressure wave into electrical potentials that are detected by the IHC. There is biological basis for proposing each of these transduction steps. The concept of electrosensitivity by the IHC provides the basis for a new view of the auditory system as presented in a recently published book, The Electromodel of the Auditory System.
Using ultrasonics to measure vibrational amplitudes of auditory organs in fish
Authors: Cox Mardi , Rogers Peter H.
Published: October 2005

A new underwater, nonintrusive technique using ultrasonics has been devised to measure the amplitude response of the fish swim bladder and otolithic organs to a low-frequency sound wave. The body of the fish is scanned with a 10-MHz source while being subjected to a single frequency sound field. The resulting echo due to the impedance mismatch at the swim bladder and otoliths is received by another 10-MHz transducer, and then fed into a spectrum analyzer. The relative magnitude between the 10-MHz peak and the side bands created by the low-frequency excitation provides the desired amplitude information. Preliminary measurements have been obtained to demonstrate the method. Further refinements will allow measurements of 25 Å over 0.1 mm. This technique is superior to previous methods using accelerometers, microphones, Laser light scattering, and holographic interferometry because all of these require that the organs be either directly exposed to the measuring device or removed from the body. [Work supported by ONR.]
Magnetic media, their characteristics and potential for sound recording and reproduction
Authors: Camras Marvin
Published: October 2005

The physical characteristics of the available magnetic media which recommend them for audio sound recording and reproduction, by both analog and digital processes, will be discussed. Inherent characteristics of each medium which affect sound quality, dynamic range, and signal-to-noise ratio will be described.
Optical media, their characteristics and potential for sound recording and reproduction
Authors: Uhlig Ronald , Marchant Allan
Published: October 2005

An overview of the present-day optical processes, including film photography, magneto-optics, and laser-optics, will be discussed. The features of the processes and local defects of the media which affect sound quality, dynamic range, and signal-to-noise ratio will be described.
Technical-esthetic considerations for sound recording
Authors: Eargle John M.
Published: October 2005

From the very beginning of sound recording, physical limitations of the medium have dictated certain esthetic constraints in the use of the medium. The major technical epochs have offered advantages to both engineer and producer, and the historical progression has provided solutions to problems in playing time, dynamic range, distortion, and space perspective. The problems associated with major format changes are almost predictable at this point. With each major change, producers and engineers have had to redefine the best fit of the message into the medium. They have invariably stumbled at first, and then rapidly learned to work the medium to the advantage of the music. In this paper we will review the fascinating interplay which has taken place between esthetics and technology over the years, concentrating on those problems associated with the coming of digital recording.
State of the art commercial music recording practice
Authors: Blinn Richard P.
Published: October 2005

The variety of steps which take place between the artist's performance and the production of the final product for sale to the consumer will be explained and their effect on the final reproduced sound will be demonstrated by means of specially prepared recordings.
Tactile devices in sensory substitution systems
Authors: Sherrick Carl E.
Published: October 2005

An overview of the research on tactile aids for the deaf, blind, and deaf-blind will pay particular attention to the problems of encoding the environmental signals in ways that the skin senses can interpret them efficiently. Following a brief summary of the early approaches to the development of systems for sensory substitution, there will be a closer examination of the efforts mounted in the past 20 years. The talk is intended to include illustrations of successful and unsuccessful efforts at device and system development from scientific and engineering studies. In addition, there will be recounted entrepreneurial experiences of a number of investigators and developers of devices and methods for improving communicative skills in the sensorily disabled population. [Work supported by NIH Grant 04755.]
Tactile aids: A comparison of single and multichannel devices
Authors: Carney Arlene Earley
Published: October 2005

The use of tactile aids as sensory prosthetic devices for the deaf has become a topic for discussion among researchers and clinicians interested in the hearing impaired. The importance of work in this area has become even greater with the increasing frequency of cochlear implants in deaf adults and children. A primary question in the area of tactile research concerns the design of the tactile device which will provide the most appropriate stimulus to the deaf subject. This presentation will focus on several studies which compared the use of a multichannel tactile device with a single-channel device for the perception of both segmental and suprasegmental aspects of speech. Results of these experiments indicated that the single-channel device provided more accurate cues for the perception of suprasegmentals, such as number of syllables per work, syllabic stress, and intonation. Further, there was no significant ditference between single- and multichannel devices for the perception of vowels and consonants. An additional experiment was done with deaf patients who had received a single-channel cochlear implant, using the same segmental and suprasegmental stimuli as in the tactile studies. A comparison of these results to those obtained with a single-channel tactile device showed no advantage for the implant, despite the wearability and experience factors in its favor. These results will be discussed in view of the long-term goals for design and tactile aids, and for their most effective use as speech training aids for the deaf.
The case for tactile aids
Authors: Miller James D. , Weisenberger Janet M.
Published: October 2005

Devices that convert sound information into vibrotactile stimulation have been shown in laboratory and clinical studies to enable persons to appreciate many aspects of the acoustic environment, and thus are of potential benefit to deaf persons. These vibrotactile devices provide information comparable to that obtained with surgical cochlear implants, but appear to have some advantages, particularly in use with children. These advantages include no invasive surgery, the ability to accommodate growth of the user, the potential to use the device for a trial period to assess its usefulness, the possibility of shared use by more than one person, and considerably lower cost. At CID, a number of vibrotactile aids ranging from single-channel commercially available aids to multichannel tactile vocoders are being evaluated. Results from studies in our own and other laboratories will be used to address such issues as the features of the acoustic environment that can or should be transmitted through a tactile aid, the differences in the information transmitted by commercially available versus experimental laboratory devices, and the technical problems that remain to be overcome in the design and evaluation of improved vibrotactile aids. [Work supported by NIH and NSF.]
A case study of the tracking skill of a deaf person with long-term tactile aid experience
Authors: Cholewiak Roger W. , Sherrick Carl E.
Published: October 2005

The paper describes a case study of Dimitry Kanievski, a deaf individual who has been using a vibrotactile aid for approximately 13 years. He has acquired the ability to lipread speakers in three languages, using the Kanievski speech-analyzing device. The report describes his communicative abilities with and without the aid in his native language, Russian, as well as in English and Hebrew. When Dr. Kanievski was tested with the De Filippo-Scott tracking technique, the aid provided for a considerable improvement in performance over unaided lipreading scores. The degree of improvement, however, was a function of several factors, in particular his unaided lipreading rate for the different languages. Plotting the ratio of aided to unaided performance against unaided tracking rate yielded a power function. [Work supported by NIH Grant NS-04775.]