bluuebunny/crossref_metadata_2025 huggingface dataset:
Counting on fingers and aloud: Stutters and controls
Authors: Borden Gloria J.
Published: October 2005

Stutterers of various degrees of severity were matched by sex and age with normal speakers. Subjects counted randomly presented series of four digits each, graded in difficulty from the easier sequential series, such as 5432, to series with no sequential items, such as 4253. The subjects counted aloud, counted silently on their fingers, and counted simultaneously on fingers and aloud. Respiratory, laryngeal, and labial movements were inferred from measures of changes in impedance across hemispheric elastic lubes on the chest and abdomen, from a laryngograph measuring impedance changes across the vocal folds, and from an optical tracking system measuring X-Y movements of an LED attached to the lower lip. A glove producing different voltages for each digital contact was used to record the finger counting. Although there were no universal deviations from normal coordination during the fluent utterances of the stutterers, the more severe the stuttering, the more the labial and respiratory movements were discoordinated in addition to the laryngeal movements. Stutterers on the average also took longer to execute the manual task than nonstutterers. [NIH supported.]
Compensatory responses to low magnitude loads applied to the lower lip during speech
Authors: Abbs James H. , Gracco Vincent L.
Published: October 2005

Unanticipated inferiorly directed loads were applied to the lower lip during speech using a torque motor under force feedback control. Loads well within the physiological force range of the labial musculature (10–15 gms) were chosen to ensure meaningful interpretation of ‘normal’ compensatory processes. Loads were applied on less than 15% of the utterance repetitions so as to minimize performance artifacts due to perturbation-induced conscious or unconscious motor adaptation. Compensatory EMG changes reflecting both closed-loop feedback as well as open-loop feedforward control processes were observed. These compensations, seen the first time the load was applied, included increased agonistic muscle activity (001, Mentalis), reductions in antagonistic muscles (DLI) as well as goal-oriented increases of upper lip muscle activity (OOS). Observation of EMG compensations from one load trial to another also revealed tradeoffs between muscles, apparently reflecting motor equivalence capabilities. These findings will be discussed relative to the role of afferent mechanisms in the autogenic control of individual movements and in the coordination of multiple speech gestures. [Supported in part by NINCDS program Project Grant NS-13274.]
An improvement in the range resolution of ultrasonic pulse echo systems by deconvolution
Authors: Carpenter R. N. , Stephanishen P. R.
Published: October 2005

Ultrasonic pulse echo systems are often limited in range resolution by the bandwidth of the piezoelectric transducer. Significant improvements in the range resolution of such systems can be obtained by minimizing the effects of the transducer's dynamic response on the overall pulse echo process. An approach to minimize the effects of the transducer is developed from linear system and impulse response techniques. In essence, the pulse echo voltage of interest is deconvolved with a pulse echo reference voltage which is obtained from an air/water interface in the near field of the transducer. A computer study of the pulse echo process and the deconvolution process is presented to illustrate the nature of the improvement in range resolution for several cases of interest. Finally, experimental results are presented to illustrate the improvement using commercially available transducers. [Work supported by NIH.]
Acoustic ground impedance meter
Authors: Zuckerwar Allan J.
Published: October 2005

A compact, portable instrument has been developed to measure the acoustic impedance of the ground, or other surfaces, by direct pressure—volume velocity measurement. A Helmholz resonator, constructed of heavy-walled stainless steel but open at the bottom, is positioned over the surface having the unknown impedance. The resonator chamber measures 0.229 m in diameter by 0.152 m high. The sound source, a cam-driven piston of known stroke and thus known volume velocity, is located in the neck of the resonator. The cam speed is variable up to a maximum 3600 rpm. The sound pressure at the test surface is measured by means of a microphone flush—mounted in the wall of the chamber. An optical monitor of the piston displacement permits measurement of the phase angle between the volume velocity and the sound pressure, from which the real and imaginary parts of the impedance can be evaluated. Measurements using a five-lobed cam can be made up to 300 Hz; these can be extended by means of a 15-lobed cam, presently under fabrication, to nearly 1000 Hz. Detailed design criteria and results on a soil sample will be presented.
Interaction of spontaneous acoustic emissions with external tones
Authors: Rabinowitz W. M. , Widin Gregory P.
Published: October 2005

In certain individuals, spontaneous acoustic emissions (SAE's) can be measured in the external auditory meatus; such SAE's can be suppressed by introducing an external tone [P.M. Zurek, J. Acoust. Soc. Am. 69, 514– 523 (1981)]. The suppression of SAE level is quite abrupt (20 dB or more suppression per 5 dB increase in suppressor level) for suppressor frequencies below and just above that of the SAE; however, the growth of suppression becomes more gradual as suppressor frequency increases above the SAE. A release from suppression can be demonstrated by the interaction of an SAE and two external tones. When a tone above the SAE frequency causes suppression, a second tone above the suppressor frequency can cause the SAE to return nearly to its ambient level. (The SAE in this case is clearly distinguishable from distortion products.) This result is consistent with the second tone having suppressed the effective level of the suppressor. [Work supported by NIH.]
The morphology of inner hair cell stereocilia in the mouse
Authors: Saunders James C. , Garfinkle Terry J.
Published: October 2005

This study examined with SEM the stereocilia of inner hair cells in the juvenile C57BL/6J mouse. Three measures were sought: the number of stereocilia per hair cell, and stereocilia height and width in the three rows on each hair cell. The number of stereocilia per hair cell decreased from base to apex. Conversely, the height of the tallest row increased by 300%, the middle row by 100%, and the shortest row by 30% from base to apex. Stereocilia width remained fairly constant across the cochlea. The total stereocilia surface area per hair cell increased by 143% from the base to the apex. However, the approximate surface area shielded from the extracellular fluid environment, because the surface of two adjacent stereocilia were in contact with one another, was found to be nearly a constant fraction of the total stereocilia surface area, across the cochlea. The height variations of the tallest stereocilia may be related to the frequency-resolving properties of the cochlea, while the constant fraction of hidden to total surface area may be related to the hair cell transduction process. [Work supported by the Deafness Research Foundation.]
Remote acoustic classification of marine sediments
Authors: Cochrane N. A.
Published: October 2005

Acoustic echosounding is used to classify shallow marine sediments on the basis of three quantitative parameters—the total echo spatial coherence at 3 and 10 kHz [Dunsiger et al., IEEE J. Ocean. Eng. 6, (in press)] and a subbottom windowed spatial coherence ratio (Q41 ratio) at 3 kHz. Echo coherence measures the frequency dependence of combined incoherent surface and volume scattering, the Q41 ratio measures the character of sediment internal layering. A HUNTEC DTS boomer supplies the highly reproducible broadband impulses required for optimum selection and use of these parameters. Five distinct sediment types in Placentia Bay, Newfoundland ranging from coarse gravels to clays are investigated. A classification consistency of 70%->90% is realized over visually uniform sections on analysis of clusters of 50 pings. The technique appears capable of resolving very subtle variations observed on corresponding grey scale records.
Occurrence and acoustical significance of natural gas hydrates in marine sediments
Authors: Daniels J. Mark
Published: October 2005

The current knowledge of natural gas hydrates in marine sediments is reviewed. The Chemical structure, occurrence in nature, conditions of formation and acoustic properties of natural gas hydrates are discussed. Conditions suitable for the formation of this icelike crystalline structure, which traps the gas molecule within it, are found over 90% of the ocean floor. The hydrate structure can greatly increase compressional sound velocity and alter shear velocity and absorption processes from those expected for typical marine sediment types. The potential impact of hydrates on underwater acoustics is demonstrated through computations of bottom reflection loss for hypothetical subbottom structures containing hydrate zones. [Work sponsored by Naval Oceanographic Research and Development Activity.]
Acoustic reflection and transmission coefficients at a planar interface of a porous medium exhibiting fast and slow compressional waves
Authors: Johnson David Linton , Plona T. J.
Published: October 2005

We have measured the reflected and transmitted amplitudes of ultrasonic pulses at normal incidence on a layer of water-saturated fused glass beads in which Biot slow compressional waves have been observed. [T. J. Plona, Appl. Phys. Lett, 36, 259 (1980).] We have investigated water-porous medium interfaces and solid-porous medium interface; in the latter case, the nature of the bond is of critical importance to the amplitude of the slow wave generated at the interface. Due to mode conversion upon internal reflection, a pulse may traverse the latter as either a fast or a slow compressional wave. The results are interpreted in terms of boundary conditions derived from a general Lagrangian formulation derived previously.
A study of bounded beam reflection on plates and half-spaces using least-squares approximation
Authors: Leroy O. , Claeys J. M.
Published: October 2005

Using a least-square approximation for incident beam profiles we calculate the reflected profiles at liquid-solid and liquid-solid-liquid interfaces. The results are compared to those obtained by [Bertoni and Tamir, “Unified theory of Rayleigh-angle phenomena for acoustic beams at liquid-solid interfaces,” Appl. Phys. 2, 157–172 (1973)] for half-spaces and [Pitts et al., “Theory of nonspecular reflection effects for an ultrasonic beam incident on a solid plate in a liquid,” IEEE Trans. Sonics Ultrason. SU-24, No. 2 (March 1977)] for plates. This method presents several advantages: calculations are less complicated, profiles can be calculated at any angle of incidence, one always obtains an analytical expression for the reflected profile whether reflection from plates or half-spaces is considered.
Whale observations and acoustic noise measurements around Kahoolawe Island, Hawaii
Authors: Friedl William A. , Thompson Paul O.
Published: October 2005

Seven SSQ-57A sonobuoys were monitored for seven hours from a P-3 aircraft during a surface gunfire operation north of Kahoolawe Island, Hawaii, in February 1980. Whale location and activity were also monitored from the aircraft and from Maul Island during the exercise. Humpback whale (Megaptera novaeangliae) phonations dominated the ambient noise field during the exercise. The phonations' fundamental component was near 500 Hz. The gunfire source level was approximately 10 dB below the whales' phonation level; the gunshots' peak energy was near 70 Hz. We saw whales swimming, lying still, diving, surfacing and, in two isolated instances, breeching and lob-tailing. No standards exist to evaluate the effects of the noise on marine mammals. We cannot relate the movements and activities of whales observed during the exercise to any obvious airborne, surface, or subsurface causes. [Work supported by the Naval Surface Weapons Center.]
Possible effects of offshore drilling noise on marine mammals
Authors: Turl Charles W.
Published: October 2005

This paper will present noise data for offshore drilling activities, identify species of marine mammals found in existing or proposed offshore lease areas, summarize the underwater hearing of selected species of marine mammals and differentiate between potential short-term and long-term effects of underwater noise on marine mammal populations.
Near shore ambient noise off the North Slope of Alaska
Authors: Cummings William C. , Ellison William T. , Holliday D. V.
Published: October 2005

Shallow water (1.5- to 55-m depth) ambient noise measurements (10 Hz to 10 kHz) were made at a number of locations off the North Slope of Alaska including four sites off Barrow in May/June 1980, two sites off the McClure Islands in June 1980, and 24 sites within a 100-km radius of Prudhoe Bay in September/October 1980. Measurements were made to establish baseline ambient noise levels in areas typical of the spring habitats of the bearded and ringed seals as well as the spring and fall migration paths of the bowhead and beluga whales. Data were taken under a variety of sea ice conditions ranging from heavily pressure-ridged first year (1 to 2 m thick) shorefast spring ice through ice free to fall freezeup and full ice cover conditions. The fall data includes measurements made under transitional “grease” and “pancake” ice conditions. The maximum wind speed under which data were taken was 8.2 m/s. Average spectrum levels varied from 50 to 90 dB re 1 μPa/Hz1/2 in the 10- to 1000-Hz band, and from 30 to 70 dB in the 1- to 10-kHz band. [Work supported by Alaska Eskimo Whaling Commission.]
The effect of duration on masker profile analysis
Authors: Spiegel Murray F. , Green David M.
Published: October 2005

Randomizing the frequency of a sinusoid partially masked by random noise elevates the detection threshold by no more than 3 dB. One possible explanation for this fact is that the detection process may be a profile analysis—the detector simultaneously compares the levels across critical bands and notes any extreme deviations from the mean as the potential signal. To test this idea we ran an unusual two-interval forced-choice task in which the overall level of the two intervals was a random variable. When the masker duration was 115 ms, thresholds were elevated by only 1 dB when the masker levels were varied over a 40-dB range. For shorter duration (5 ms) the spectrum is more variable and the effects randomizing level are larger, about 10 dB. Frequency uncertainty effects, with fixed levels of masker, are about 3 dB with the long duration signal and about 6 dB with the short duration signal. [Work supported by NIH.]
Masking patterns for synthetic vowels determined in simultaneous and forward masking
Authors: Moore Brian C. J. , Glasberg Brian R.
Published: October 2005

Two synthetic vowels (/i/ and /æ/) with a fundamental frequency of 100 Hz served as maskers for brief (5 ms or 15 ms) sinusoidal signals. Threshold was measured as a function of signal frequency, for signals presented immediately following the masker (forward masking) or just before the cessation of the masker (simultaneous masking). Three different overall masker levels were used: 50, 70, and 90 dB SPL. In order to compare the data from simultaneous and forward masking, and to compensate for the decay of masking in forward masking, each signal threshold was expressed as the level of a flat-spectrum noise which would give the same masking [see B. C. J. Moore and B. R. Glasberg, “Auditory filter shapes determined in simultaneous and forward masking,” J. Acoust. Soc. Am. (in press)]. The internal representation of the formant structure of the vowels, as inferred from the masking patterns, was enhanced in forward masking and “blurred” in simultaneous masking, in comparison to the physical spectra.
Dependence of psychophysical tuning curves on probe bandwidth: Relation to critical bandwidth
Authors: Gabriel Sandra , Durrant John D. , Lovrinic Jean
Published: October 2005

Psychophysical tuning curves were measured for seven normal-hearing subjects for synthetic narrow band noise probes of bandwidths 1, 150, 300, 600, 1200, and 2400 Hz, each geometrically centered at 2000 Hz. Tip length, tip bandwidth, and Q10 dB were determined for each probe bandwidth for each subject. Using a two-segment linear-fit approach, frequency “breakpoints” were determined at which responses for each tuning curve measure changed as a function of bandwidth for each subject. Critical bandwidth was also measured for each subject, using each of the same synthetic stimuli to mask a 2000-Hz pure tone. Analysis of the breakpoints for each of the three tuning curve measures and the critical bandwidth failed to reveal any statistically significant differences between the four measures. Results indicate that, for this group of normal-hearing listeners, psychophysical tuning curve parameters are reasonable estimators of the critical bandwidth.
Interaural time and amplitude differences together
Authors: Cohen Marion F. , Koehnke Janet , Gregorio Patricia A.
Published: October 2005

Interaural time jnds were measured for a 500-Hz and 1000-Hz tone-burst signal using a 2IFC adaptive procedure. The time delay was presented to one ear in one interval. In addition, an interaural amplitude difference was presented simultaneously. Thus, perceptual movement was created by both an interaural time difference and an interaural amplitude difference, which either reinforced or opposed each other (i.e., time delay accompanied by amplitude increase or decrease). With the interaural amplitude difference remaining constant for each jnd measurement, the interaural time jnd was determined for alpha ranging from +2 dB to −2 dB in 12 dB steps. Results indicate that combining the interaural amplitude difference and interaural time difference so that they reinforce each other decreases the interaural time jnds. That is, when each is below threshold, they combine to be detectable. Similarly, when they oppose each other the interaural time jnd increases. The trading ratio (μsec/dB) is substantially larger when time and amplitude are in opposition than when they reinforce each other.
Dynamic tension in water induced by the reflection of shock waves
Authors: Pullen Glenn L. , Marston Philip L.
Published: October 2005

Negative pressures were produced in distilled water by reflecting a 70-bar shock pulse off a quasi-free water-Mylar-air interface. The incident pulses, created by symmetric impact of a projectile onto a buffer, had durations of 1–2 μs. A displacement inter-ferometer measured the velocity u of the Mylar. After the pulse's trailing edge reaches the Mylar, u would tend to vanish in the absence of cavitation. If the region of tension cavitates abruptly when a tensile strength S is exceeded, the downward transition in u is terminated. The transition was observed to be terminated when u changed by Δu ≈ −4 m/s. Assuming the flow remains uniaxial, S ≈ −p0 − ρcΔu/2, where ρ, c, and p0 = 1 bar are the water's initial density, sound speed, and pressure [P. L. Marston and G. L. Pullen, Proc. of the 1981 APS Conference on Shock Waves in Condensed Matter, edited by W. J. Nellis (to be published)]. It appears that the Mylar separated from the water during pullback and the data places only a lower limit (28 bars) on S. [Work supported by ONR and the WSU Research and Arts Committee. P. Marston is an Alfred P. Sloan Research Fellow.]
Radial current density measured in guinea pig cochlea
Authors: Brownell W. E. , Manis P. B.
Published: October 2005

The spatial distribution of electrical potentials in scala tympani was measured along a radial path parallel to and beneath the basilar membrane. Recordings were made every 10 μm as an electrode was advanced toward the modiolus from the spiral ligament. Access to scala tympani was achieved by chipping and picking a hole in the third turn of the otic capsule. The hole extended from the lower lip of the spiral ligament basally to the stria vascularis apically. A low-impedance micropipette was used to measure the potential against a reference electrode inserted in the neck muscles. Click-evoked potentials varied as a function of position along the electrode's path. The current density was calculated from the observed potential gradients, and revealed position-dependent radial currents oriented both toward and away from the modiolus. Condensation clicks produced current density maxima at two locations with a separation of about 100 μm. The modiolar maximum was located below inner hair cells and was also present in response to rarefaction clicks. The results show that potential gradients related to intracochlear ionic flow can be measured in the fluid spaces of the cochlea. [Supported by grants from NIH and NSF.]
Acoustic absorption in aqueous the mixtures at 25°C
Authors: Rajagopalan S. , Tiwari Surendra A.
Published: October 2005

We report the ultrasonic absorption in aqueous mixtures of tetrahydrofuran at 25°C in the frequency range 0.27–561 MHz. The results are analyzed by the single and double relaxation model approach. Variation with concentration of the relaxation parameters is discussed in the light of molecular interactions present. It is found that the double relaxation model is more adequate to explain the observed absorption behavior than the single relaxation. The concentration, at which the peak absorption occurs, is found to be drifting from 0.3 at lower frequencies to 0.5 at higher frequencies.
Shuttle tile environments and loads
Authors: Muraca R. J.
Published: October 2005

This paper will discuss the Shuttle tile ascent environments and outline the procedures used to convert these environments into tile loads. Testing which was performed to quantify or verify the loads will also be discussed along with the load combination rationale. The discussion of the ascent environment will be limited to the transonic/supersonic portion of the mission and to specific regions of the vehicle, in particular those regions in which undensified critical (black) tiles are located. Defining tile loads presented a somewhat unique problem in that it was necessary to define the loads on each tile. The induced environments can be broken down into three categories. The first of these are aerodynamic environments. These, in turn, are broken down into two categories—(1) quasisteady, which includes spatial surface pressure gradients, pressure differentials due to vent lag, and skin friction, and (2) the unsteady aerodynamics. The second induced environment is defined as substrate vibration which results from the acoustic environment to which the substrate is subjected. The third environment is defined as a quasi-steady substrate deflection which results from a pressure loading normal to the skin and inplane loads.
Buffet loads on Shuttle Thermal Protection System tiles
Authors: Coe C. F.
Published: October 2005

This paper presents results of wind tunnel and acoustic tests to investigate buffet loads on Shuttle Thermal Protection System (TPS) tiles. It also describes the application of these results to the prediction of tile buffet loads for the first Shuttle flight into orbit (STS-1). The tests were conducted in wind tunnels at transonic and supersonic Mach numbers and in a progressive wave tube. The wind tunnel tests included single tiles of various thicknesses and arrays of tiles mounted on both rigid and elastic substructures. The corresponding acoustic tests were of the single tiles only. In most cases the “test” tiles were of Orbiter qualified material and they were bonded to the panels and proof-loaded in accordance with flight-vehicle specifications. The fixtures for the panel installations in the wind tunnels were designed to simulate flow regions on the Orbiter where shock waves and related high pressure gradients and high dynamic loads would occur. The results of the wind tunnel tests indicate that significant tile buffet loads occurred due to separated flows and oscillating shocks. Separated flow excitation caused higher buffet loads than oscillating shocks for a given level of excitation, however, the highest combined steady and dynamic loads occurred when shock waves with ΔP > 1.5 psi were on tiles.
Shuttle Orbiter acoustic fatigue certification testing
Authors: Stevens R. A.
Published: October 2005

The Space Shuttle Orbiter is designed to a unique combination of loads and environments not previously encountered in aerospace practice because the reusable Shuttle is launched like an expendable space vehicle and the Orbiter lands horizontally like a conventional aircraft for the specified 100 mission-life of the Orbiter. The Orbiter is subjected to structural vibration caused by engine exhaust-generated acoustic noise during liftoff and aerodynamic noise during atmospheric flight. A requirement was established to certify the Orbiter structure, Thermal Protection Subsystem (TPS), mechanisms, equipment, etc. and to gather empirical data to support fatigue analyses and update vibration and internal noise criteria before the completion of the Orbiter flight test program (OFT). The requirement has largely been satisfied by completing a comprehensive acoustic fatigue development and certification test program. This paper addresses the certification portion of the program including test article selection, objectives, results, and conclusions. Also included are comparisons of ground and flight test data.
The Shuttle Orbiter DI-19 multienvironmental test program
Authors: Himelblau H. , Shepherd C. C. , Rucker C. E.
Published: October 2005

DI-19 testing is presently in progress at NASA/LaRC to certify a critical section of the Orbiter lower forward fuselage structure/Thermal Protection Subsystem (TPS) to a combination/sequence of multienvironments simulating shuttle flight conditions. These environments and/or loads, and the flight events which are simulated, include: (a) rain as found on the pad, (b) combined acoustic noise and inplane static loading, (c) combined acoustic noise and inplane and differential pressure (ΔP) static loading in simulation of the ascent transonic/qmax period, (d) combined ascent heating and vacuum, (e) combined orbit cold soak and vacuum, (f) entry heating/vacuum profile, (g) combined acoustic noise and inplane and ΔP static loads in simulation of the post-entry qmax period, and (h) landing inplane static loading. The unique test facilities and procedures are described, as well as some of the results obtained during the first 16 mission exposure used to certify the structure/TPS for the four-mission Orbiter Flight Test Program. The relationship of DI-19 to the Orbiter Acoustic Fatigue Certification Test Program, which is performed at ambient atmospheric conditions and no static loads, is also described.
The development and verification of Shuttle Orbiter random vibration test requirements
Authors: Coody M. C. , Pratt H. K. , Newbrough D. E.
Published: October 2005

The unique Space Shuttle vehicle size, weight, and configuration have given rise to problems in determining vibration requirements and in verifying structural integrity for anticipated mission environments. The application of large-scale vibration testing has played a prominent part in qualifying the Shuttle for its intended missions. Extensive excitation from rocket engine acoustic, aerodynamic noise, and on-board equipment vibration are severe environments expected on each Shuttle flight. Scale model wind tunnel and hot rocket firing test results, as well as full-size rocket engine data were relied on significantly to define the random forcing functions. The determination of structural response to these environments are described herein, as well as evaluations of measured flight data and comparison with predicted design and test criteria.
Neural correletes of masked threshold
Authors: Fay Richard R. , Coombs Sheryl
Published: October 2005

The detectability of tonal and noise signals was measured in the goldfish using classical respiratory conditioning at various levels of a continuous broadband noise masker, and as a function of signal duration. At threshold for an 800-Hz tone, the signal-to-noise ratio (E/N0 = 22 dB and is generally independent of noise level and signal duration. The response of single eighth nerve fibers of the goldfish was measured under identical acoustic conditions and at the same N0 levels used in the psychophysical studies. For E/N0 below 22 dB, phase-locking to the signal occurs, but spike rate is not different from that evoked by noise alone. At E/N0 = 22 dB, the coefficient of synchronization tends to equal 0.5, and spike rate begins to rise above that evoked by noise alone. For E/N0 above 22 dB, synchronization begins to saturate and log spike rate grows linearly with signal level in dB. This function reaches a maximum slope of a doubling of driven rate per 3 dB increase in signal level under optimum conditions. Near E/N0 = 22 dB, the number of spikes evoked by a tone burst signal is linearly related to signal energy. While we are not able to determine whether masked signal detection is based upon synchronization or spike rate criteria, it is clear that behavioral detection is not based on synchronization values below 0.5.
Neurophysiological measurements of temporal discrimination in an anuran amphibian
Authors: Hillery Cynthia M.
Published: October 2005

Two experiments to assess the ability of midbrain neurons in Hyla chrysoscelis to encode the temporal structure of acoustic stimuli were performed. A fast component of the average evoked potential (AEP), measured as a peak-peak potential, provided a quantitative measure of rapid, synchronized activity in neuron subpopulations. (1) Using amplitude modulated sound stimuli, the just detectable depth of modulation as a function of modulation frequency was determined and produced neural modulation detection functions which showed bandpass characteristics with best modulation frequency between 60–200 Hz. Modulation depths between 100%-6% were clearly detectable by the animals. (2) The masking effects of broadband noise on the response to a train of pure-tone pulses was examined. The dynamic range of masking (AEP amplitude versus noise spectrum level) ranged from 20–30 dB. From these measures the CR band for the population of neurons sampled can be determined. Identical measurements were performed using the whole nerve action potential recorded from the eighth nerve in this species. Differential ability to encode temporal structure of acoustic stimuli peripherally and centrally was examined.
Auditory responses in a vocal nucleus of the leopard frog Rana pipiens: Characterization and effects of hormones
Authors: Aitken Peter G. , Capranica Robert R.
Published: October 2005

Auditory-evoked responses of single neurons were studied in the pretrigeminal nucleus of leopard frogs; this nucleus is involved in the control of vocal output [R. S. Schmidt, J. Comp. Physiol. 108, 99–113 (1976)]. Frogs receiving hormone treatment (human chorionic gonadotropin, 25 u subcutaneously daily for 5 to 14 days) and untreated frogs were used. There was a significantly greater probability (chi-squared = 9.66, df = 1, p < 0.01) of encountering auditory activity in this nucleus in hormone-treated frogs, but there was no apparent difference between the groups in the characteristics of the evoked activity. Most units showed V-shaped tuning curves with best excitatory frequencies ranging from 350–1100 Hz, thresholds from 31–87 dB SPL, and Q(10 dB) from 1.2–5.1. Response latencies varied from 10–50 ms and dynamic ranges from 20–40 dB. Both phasic and tonic response patterns were seen. Approximately 10% of the units would not respond to pure tones except at intensities above 100 dB; these units would respond to white noise, with thresholds between 50 and 70 dB SPL. This auditory input to the vocal system may play a role in acoustically evoked mate calling. [Supported by N.I.H.]
Tonotopic and anatomical organization of inferior colliculus in the mustache bat, Pteronotus p. parnellii
Authors: Zook J. M. , Bodenhamer R. D. , Pollak G. D.
Published: October 2005

This study combined single-unit recording with electrophoretic deposits of Alcian Blue and horseradish peroxidase. Within the central nucleus of the inferior colliculus we find three physiologically distinct regions which are closely correlated with three cytoarchitectonically defined divisions. The anterolateral division contains units with low best frequencies (18 to 60 kHz). This area has a clear laminar organization of cells and dendrites visible in either Nissl-stained or Golgi sections cut in the horizontal plane. Laminae sheets extend medial-lateral while the tonotopic organization runs perpendicular to these sheets from high posterodorsal to low anteroventral. The medial division contains units with high best frequencies (62–114 kHz). This region is posteromedial to the anteriolateral division and lacks a clear laminar organization. The dorsal division contains only units with best frequencies in a narrow range around 61–62 kHz. This division occupies more than one-third of the entire inferior colliculus and lies mainly dorsal and posterior to the anterolateral division. It lacks a clear laminar organization and can be distinguished from the medial division by cell size and packing density.
Identifying vowels in CVC syllables: Effects of inserting silence and noise
Authors: Diehl Randy L. , Parker Ellen M.
Published: October 2005

Listeners were asked to identify natural vowels in /d_d/ context under various deletion conditions. Deletion intervals ranged from 60% to 90% of the syllable duration (measured from initial burst to final closure onset) and were centered about the midpoint. The deleted syllable portions were replaced with either silence or broadband noise. In one experiment, the three syllable types used were /did/, /ded/, and /dud/; in the other experiment, the three syllable types were /dΙd/, /dεd/, and /dΛd/. To ensure that identification performance was based solely on spectral information, tokens were selected such that, within an experiment, average syllable duration was approximately equal across types. Identification performance in the 60% and 70% deletion conditions was not substantially worse than for full syllables [cf., W. Strange, J. J. Jenkins, and T. R. Edman, J. Acoust. Soc. Am. Suppl. 1 61, S39 (1977)]. Even the 90% deletion conditions yielded performance well above chance, indicating that significant vowel information is contained in the first and last 10 or 15 ms of the syllable. Results will be discussed in terms of residual acoustic cues.
Fundamental frequency and vowel perception
Authors: Ryalls John H. , Lieberman Philip
Published: October 2005

The set of nine nondiphthong vowels of American English were synthesized using the averaged male values from Peterson and Barney (1952). These vowels were produced in three conditions of the fundamental frequency: (1) average 135 Hz, (2) low 100 Hz, and (3) high 250 Hz. In forced-choice testing, subjects identified vowels in the average and low condition of the f0 with greater accuracy than the high f0 vowels. A second experiment was conducted using the female formant frequency values from Peterson and Barney and the same conditions of f0. Subjects still performed better on the low and average condition of the f0 for these vowels. These results suggest that the human formant frequency extractor is aided by the more detailed transfer function of a lower fundamental. The pattern of vowel errors was not the same across f0 conditions nor was it the same across male or female formant values. The point vowels [i], [u], and to a lesser degree [a] were the most consistently identified across conditions of the fundamental.
Recognition of cross-modal correspondences between the visual and auditory products of articulation in early infancy: Report on a method and preliminary data
Authors: Kuhl Patricia K. , Meltzoff Andrew N.
Published: October 2005

We have developed an experimental procedure for studying the recognition of cross-modal correspondence between the visual and auditory products of articulation in early infancy. In a series of experiments, infants were presented with filmed displays of two faces, one producing the articulatory movements corresponding to the vowel [a] and the other producing the movements corresponding to the vowel [i]. One of the sound tracks (either [a] or [i]) was played in synchrony with the faces. The infants' visual fixations to the two films were scored by an observer who could not hear the sound track presented to the infant nor see the faces. We hypothesized that an infant's visual preference for one of the two faces would be influenced by the auditory signal that was presented. The temporal synchrony of the visual and auditory stimuli could be adjusted, allowing us to separate the infant's ability to recognize (i) the structural correspondence between a visual and an auditory event from (ii) the temporal synchrony between a visual and an auditory event. Preliminary data on infants under six months of age will be presented. [Work supported by NSF.]
Assessment of individual phonetic discrimination performance using factor analysis
Authors: Kitselman Kurt P. , Divenyi Pierre L.
Published: October 2005

The purpose of this study was to determine the usefulness of Q-type factor analysis [F. N. Kerlinger, Foundations of Behavioral Research (Holt, Rinehart, & Winston, New York, 1973)] for obtaining an objective measurement of individual phonetic discrimination performance. Five conditions of phonetic contrasts were presented to ten aphasic and ten control subjects in a standard AX discrimination paradigm. The first analysis of group differences utilized the average discrimination profiles which were compared between groups within each stimulus conditions using the rank correlation procedure applied under similar conditions by Liberman et al. [J. Exp. Psychol. 61, 379–388 (1961)]. The weakness of this method is that individual discrimination performances are ignored. This problem may be alleviated through the use of Q-type factor analysis. The results of this analysis consisted of a loading value on the principle factor for each subject within each stimulus condition. Only the subjects with high loading exhibited discrimination profiles with the expected peaks of discrimination. Thus the loading value was interpreted as a measure of phonetic discrimination performance. Analysis of variance using the loading values produced the same results obtained in the earlier analysis, but factor analysis offered the advantage of producing a single, objective measure of discrimination performance for individual subjects, a measure that can then be compared with other behavioral measures.
Confidence ratings in discrimination of prosodic features of unintelligible sentences
Authors: Farrar C. L.
Published: October 2005

Three types of sentence materials were presented to test perception of prosodic features. The sentences differed in grammatical phrase structure, major constituent boundary (MCB), or contrastive stress. Subjects made forced-choice responses to the prosodic features and assigned a confidence rating estimating of the probability of being correct. Sentences were presented under three experimental conditions: audition alone (AUD), vision alone (VIS), and audiovisual (AV). The acoustic signal was low-pass noise, amplitude modulated by the sentence materials. Irrespective of correctness, highest ratings were assigned to responses under the AV condition, next highest to VIS, and lowest to AUD conditions. The relationship of accuracy to rating assignment varied with sentence material and experimental condition. For the test of grammatical phrase structure (5 AFC) low ratings were assigned to correct responses under AUD conditions, suggesting that these were correct guesses. In locating the MCB (16 AFC), rating assigned to correct responses were not greatly different from ratings assigned to error responses. If subjects use ratings as instructed, the probability of obtaining a correct response would correspond to the ranges of certainty for each rating category, independent of experimental condition. Under AUD and VIS conditions, subjects over- or underestimated the probability of being correct. Under AV conditions, subjects were most successful in estimating accuracy with confidence ratings. [Work done while author was at University of Virginia.]
Pressure sensor employing strain-sensitive materials
Authors: Jameson Paul W. , Ordubadi Afarin
Published: October 2005

Pressure sensors which employ strain-sensitive materials bonded to more compressible materials can have a complicated dependence on frequency and angle of incidence if the strain-sensitive material is not aligned so as to be a true volume sensor. In the case of a cylindrically shaped sensor, a true volume response is obtained if the sensor responds twice as much to radial strain as to axial strain. For a fiber optic- or polymeric-type hydrophone, the strain sensor could be wound helically at 54.7° from the axial direction to obtain a true-volume response. Other winding methods will achieve similar acoustic results, but they will reduce the ability of the sensor to bend. Sensitivity of several designs will be discussed.
An analytical theory for the response of finite elastic plates at low frequencies under heavy fluid loading
Authors: Crighton D. G. , Innes D.
Published: October 2005

The low-frequency response to concentrated excitation of a finite thin elastic plate under heavy fluid loading is examined using a generalized Wiener-Hopf approach. The plate size is assumed large in an appropriate sense, and it is shown how the solution can be derived from the exact solution for the structure-acoustic problem at the edge of a semi-infinite plate. In particular, it is shown that the reflection, with no more than a phase change dependent on the edge conditions, of a low-frequency structural wave at the edge leads to the phenomena of resonance and antiresonance very much as in the absence of fluid loading. It is then argued that exact results for infinite and semi-infinite geometries may be used to solve, approximately, a wide variety of problems in the heavy fluid loading limit which are not otherwise susceptible to analytical treatment, and also that this method in principle permits heavy fluid loading effects to be incorporated in large-scale finite element calculations for realistic structures. [Work supported by ONR, Code 222.]
Measuring the fricative differences within and between languages
Authors: Nartey Jonas N. A.
Published: October 2005

We do not know the relevant parameters for comparing fricatives in different languages. In an attempt to determine how to characterize fricatives, five speakers each of Amharic, Egyptian Arabic, English, Hebrew, Hopi, Japanese, Korean, Navaho, Papago, Pima, Polish, Yoruba, and Zuni produced fricatives in a sentence frame in the environments i-i, a-a, u-u. A 25-ms section of each fricative was subjected to a critical-band analysis (within the frequencies 0–10 kHz). The resulting auditory spectra were then compared for fricatives within and between the languages, by means of PARAFAC and other statistical techniques. These techniques enabled us to determine the extent to which fricatives which have been described as the same in different languages are, in fact, the same. [This work was supported in part by NSF, and by the Institute of American Cultures in collaboration with the American Indian Studies Center at UCLA.]
An auditory discrimination test battery
Authors: Watson C. S. , Johnson D. M. , Lehman J. R. , Kelly W. J. , Jensen J. K.
Published: October 2005

A battery of eight auditory discrimination tests was designed to measure the primary dimension along which simple and complex sounds can be discriminated. Six of the tests, selected on the basis of data collected in an earlier 22-subtest version of the battery [D. M. Johnson, J. K. Jensen, and C. S. Watson, J. Acoust. Soc. Am. Suppl. 1 67, S52 (1980)], use tonal stimuli: tests of frequency, intensity, and duration discrimination, using single tones, and tests of rhythm, temporal order, and tonal-pattern discrimination using multitone sequences. Two additional tests employ speech sounds: a syllable order discrimination test and a modification of one portion- of a nonsense syllable identification test [J. R. Dubno and H. Levitt, J. Acoust. Soc. Am. 69, 249–261 (1981)]. The tape-recorded tests were designed to be administered to groups of listeners in a free field, moderately low-reverberation environment. with responses recorded on printed forms. Seventy-two modified 2AFC trials, distributed among eight stimulus values, are presented in each of the discrimination tests. Performance of groups of listeners given successive versions of the test battery show it to be a reliable screening instrument for the measurement of auditory discrimination abilities. [Work supported by NIH/NINCDS.]
Some comparisons of intelligibility of synthetic and natural speech at different speech-to-noise ratios
Authors: Pisoni David B. , Koen Esti
Published: October 2005

Despite the extensive literature on the intelligibility of natural speech in noise, relatively little is currently known about the deleterious effects of noise on the perception (i.e., recognition, identification, and understanding) of synthetic speech. In this paper, we wish to report the results of a study that examined the effects of noise on the intelligibility of synthetically produced monosyllabic words using the traditional Modified Rhyme Test to measure intelligibility. Over a range of S/N ratios, we found that synthetic speech suffers a greater, decrement in performance than naturally produced speech. Moreover, the decrement in performance was even greater when the MRT response format was changed from a closed six-alternative forced choice procedure to an open free response format. The increase in uncertainty affected recognition of the synthetic items more than the natural ones. These findings have implications for the use of voice response systems that employ synthetic speech in noisy listening environments where intelligibility of the linguistic message may be at a premium. [Supported by a research grant from NINCDS to Indiana University.]
Acoustical properties of glass fiber roof fabrics
Authors: Moulder Ron , Merrill Jim
Published: October 2005

Woven glass cloth that has been coated with a hydrocarbon is used extensively as a roof membrane in air or tension-supported structures. Previous presentations have been made on the acoustical environment of some of these structures. This paper will focus on the acoustical properties of the roof fabric as measured in the laboratory. Sound transmission loss values were measured for two coated fabrics with and without inner liners. Tests were conducted in accordance with the ASTM test method E90-75. Sound absorption tests were also conducted on these same roof configurations in accordance with ASTM test method C423-77. The data generated from these tests should be most helpful to the designer or consultant in determining the acoustical impact both inside and outside fabric roof structures.
The effect of longitudinal wave coupling on the diffusion of flexural energy in a one-dimensional waveguide with lossy obstacles
Authors: Smith P. W.
Published: October 2005

Results of a previous power-balance analysis [J. Acoust. Soc. Am. Suppl. 1 62, S83 (1977)] are extended to include flexural-longitudinal coupling at each obstacle. For small coupling, there are two effects. (1) Coupled power constitutes another loss (in addition to dissipation and sound radiation) in determining the attenuation rate (dB/obstacle) of the flexural response diffusing from the source. (2) This power reverberates as longitudinal waves and leaks back into flexural, causing a homogeneous background of flexural response in addition to the exponentially attenuated component described in (1). Numerical results are given for a ribbed steel plate underwater. Power-balance methods that postulate highly reverberant flexural fields in each bay (e.g., Statistical Energy Analysis) overestimate the attenuation rate by a factor of about two, in this case.