bluuebunny/crossref_metadata_2025 huggingface dataset:
Safety and Efficacy of Vardenafil, a Selective Phosphodiesterase 5 Inhibitor, in Patients with Erectile Dysfunction and Arterial Hypertension Treated with Multiple Antihypertensives
Authors: Van Ahlen Hermann , Wahle Klaus , Kupper Wolfram , Yassin Aksam , Reblin Tjark , Neureither Marcus
Published: October 2005

Introduction

Vardenafil, a phosphodiesterase type 5 (PDE5) inhibitor, was evaluated in a prospective trial in the primary care setting involving hypertensive men with ED who were receiving at least one antihypertensive medication.

Aims

To investigate the safety and efficacy of flexible-dose vardenafil therapy compared with placebo in PDE5 inhibitor-naïve subjects with arterial hypertension and ED.

Methods

In this multicenter, randomized, double-blind, placebo-controlled study, 354 patients received placebo or vardenafil (5–20 mg) for 12 weeks. Primary efficacy measures were diary responses to the Sexual Encounter Profile (SEP) questions 2 (vaginal insertion) and 3 (maintenance of erection). Additional efficacy measures included positive responses to the Global Assessment Question (GAQ).

Results

Compared with placebo, vardenafil significantly improved mean SEP2 and SEP3 success rates over the 12-week study period (intention-to-treat [ITT] and last observation carried forward [LOCF]) analysis). For LOCF, SEP2 and SEP3 were 83% for vardenafil vs. 58% for placebo and 67% for vardenafil vs. 35% for placebo, respectively (P < 0.0001 vs. placebo). Improved erections (GAQ) were experienced by 80% of vardenafil-treated patients at study end, compared with 40% for placebo (P < 0.0001, LOCF). The most commonly reported treatment-emerging adverse events were headache (3.1%) and flushing (1.6%), which were mild-to-moderate and transient in nature. Importantly, there were no significant changes in systolic and diastolic blood pressure or heart rate between the vardenafil and placebo groups. The average number of antihypertensives used per patient was 1.5 and 1.4 in the vardenafil and placebo groups, respectively. Both the incidence of adverse events and the ability to maintain an erection were unaffected by stratification into distinct subsets according to the class of antihypertensive medication being received.

Conclusion

Vardenafil significantly improves EF in hypertensive men treated with concomitant antihypertensive medication, is well tolerated, and does not significantly affect blood pressure.
Healthcare providers’ perspectives: Estimating the impact of chronicity
Authors: Falkenstern Sharon K. , Loeb Susan J. , Gueldner Sarah H. , Penrod Janice , Poon Leonard W
Published: October 2005

Purpose

To compare elders’ self‐ratings of the impact of their chronic conditions with healthcare providers’ estimates of the impact of the same conditions on older adults. The effect of length of time in clinical practice and rural or urban clientele on healthcare providers’ impact ratings was also explored.

Data sources

A pen‐and‐paper survey was administered to 122 community‐dwelling adults aged 55 years and older, attending health education or exercise programs held by a hospital in a city of approximately 60,000 people. Elders were asked to identify which of 11 common chronic conditions they had and then to rate the impact each condition had on their daily lives. A sample of 290 healthcare providers who are members of the Gerontological Society of America completed a mailed survey asking them to estimate the impact that each of the 11 conditions had on older adults.

Conclusions

Healthcare providers consistently overestimated the impact that chronic health conditions had on older adults when compared with the elders’ self‐ratings of impact. Greater levels of experience were not significantly related to providers’ impact ratings of chronic conditions.

Implications for practice

Nurse practitioners, as primary care providers, must understand the impact of chronic conditions on older adults’ daily lives in order to provide effective, efficient, and evidence‐based health care. This study points to the need for more research to discover why older adults and healthcare providers have such different perspectives on the impact of chronic health conditions.
Transmission properties of bone conducted sound: Measurements in cadaver heads
Authors: Stenfelt Stefan , Goode Richard L.
Published: October 2005

In the past, only a few investigations have measured vibration at the cochlea with bone conduction stimulation: dry skulls were used in those investigations. In this paper, the transmission properties of bone conducted sound in human head are presented, measured as the three-dimensional vibration at the cochlear promontory in six intact cadaver heads. The stimulation was provided at 27 positions on the skull surface and two close to the cochlea; mechanical point impedance was measured at all positions. Cochlear promontory vibration levels in the three perpendicular directions were normally within 5dB. With the stimulation applied on the ipsilateral side, the response decreased, and the accumulated phase increased, with distance between the cochlea and the excitation position. No significant changes were obtained when the excitations were on the contralateral side. In terms of vibration level, the best stimulation position is on the mastoid close to the cochlea; the worst is at the midline of the skull. The transcranial transmission was close to 0dB for frequencies up to 700Hz; above it decreased at 12dB∕decade. Wave transmission at the skull-base was found to be nondispersive at frequencies above 2kHz whereas it altered with frequency at the cranial vault.
Phonetic identification in quiet and in noise by listeners with cochlear implants
Authors: Munson Benjamin , Nelson Peggy B.
Published: October 2005

This study examined the effect of noise on the identification of four synthetic speech continua (/rɑ/-/lɑ/, /wɑ/-/jɑ/, /i/-/u/, and say-stay) by adults with cochlea implants (CIs) and adults with normal-hearing (NH) sensitivity in quiet and noise. Significant group-by-SNR interactions were found for endpoint identification accuracy for all continua except /i/-/u/. The CI listeners showed the least NH-like identification functions for the /rɑ/-/lɑ/ and /wɑ/-/jɑ/ continua. In a second experiment, NH adults identified four- and eight-band cochlear implant stimulations of the four continua, to examine whether group differences in frequency selectivity could account for the group differences in the first experiment. Number of bands and SNR interacted significantly for /rɑ/-/lɑ/, /wɑ/-/jɑ/, and say-stay endpoint identification; strongest effects were found for the /rɑ/-/lɑ/ and say-stay continua. Results suggest that the speech features that are most vulnerable to misperception in noise by listeners with CIs are those whose acoustic cues are rapidly changing spectral patterns, like the formant transitions in the /wɑ/-/jɑ/ and /rɑ/-/lɑ/ continua. However, the group differences in the first experiment cannot be wholly attributable to frequency selectivity differences, as the number of bands in the second experiment affected performance differently than suggested by group differences in the first experiment.
Comparison of an analytic horn equation approach and a boundary element method for the calculation of sound fields in the human ear canal
Authors: Stinson Michael R. , Daigle Gilles A.
Published: October 2005

The sound field inside a model human ear canal has been computed, to show both longitudinal variations along the canal length and transverse variations through cross-sectional slices. Two methods of computation were used. A modified horn equation approach parametrizes the sound field with a single coordinate, the position along a curved center axis—this approach can accommodate the curvature and varying cross-sectional area of the ear canal but cannot compute transverse variations of the sound field. A boundary element method (BEM) was also implemented to compute the full three-dimensional sound field. Over 2000 triangular mesh elements were used to represent the ear canal geometry. For a plane piston source at the entrance plane, the pressure along the curved center axis predicted by the two methods is in good agreement, for frequencies up to 15kHz, for four different ear canals. The BEM approach, though, reveals spatial variations of sound pressure within each canal cross section. These variations are small below 4kHz, but increase with frequency, reaching 1.5dB at 8kHz and 4.5dB at 15kHz. For source configurations that are more realistic than a simple piston, large transverse variations in sound pressure are anticipated in the vicinity of the source.
Study of the brightness of trumpet tones
Authors: Poirson Emilie , Petiot Jean-François , Gilbert Joël
Published: October 2005

This study focuses on a particular attribute of trumpet tones, the brightness, and on the physical characteristics of the instrument thought to govern its magnitude. On the one hand, an objective study was carried out with input impedance measurements, and, on the other hand, a subjective study with hearing tests and a panel of subjects. To create a set of different trumpets a variable depth mouthpiece was developed whose depth can be easily and continuously adjusted from “deep” to “shallow.” Using this mouthpiece and the same trumpet, several instruments were generated which may be played in three ways: (i) by a musician, (ii) by an artificial mouth, and (iii) using physical modeling simulations. The influence of the depth of the mouthpiece on the perception of the trumpet’s tones was investigated, and the ability of a musician, the artificial mouth, or physical modeling simulations to demonstrate perceptively noticeable differences was assessed. Physical characteristics extracted from the impedance curves are finally proposed to explain the brightness of trumpet tones. As a result, the physical modeling simulations now seem to be mature enough to exhibit coherent and subtle perceptual differences between tones. This opens the door to virtual acoustics for instrument makers.
Behavioral and auditory evoked potential audiograms of a false killer whale (Pseudorca crassidens)
Authors: Yuen Michelle M. L. , Nachtigall Paul E. , Breese Marlee , Supin Alexander Ya.
Published: October 2005

Behavioral and auditory evoked potential (AEP) audiograms of a false killer whale were measured using the same subject and experimental conditions. The objective was to compare and assess the correspondence of auditory thresholds collected by behavioral and electrophysiological techniques. Behavioral audiograms used 3-s pure-tone stimuli from 4to45kHz, and were conducted with a go∕no-go modified staircase procedure. AEP audiograms used 20-ms sinusoidally amplitude-modulated tone bursts from 4to45kHz, and the electrophysiological responses were received through gold disc electrodes in rubber suction cups. The behavioral data were reliable and repeatable, with the region of best sensitivity between 16 and 24kHz and peak sensitivity at 20kHz. The AEP audiograms produced thresholds that were also consistent over time, with range of best sensitivity from 16to22.5kHz and peak sensitivity at 22.5kHz. Behavioral thresholds were always lower than AEP thresholds. However, AEP audiograms were completed in a shorter amount of time with minimum participation from the animal. These data indicated that behavioral and AEP techniques can be used successfully and interchangeably to measure cetacean hearing sensitivity.
Acoustic analysis of a computer cooling fan
Authors: Huang Lixi , Wang Jian
Published: October 2005

Noise radiated by a typical computer cooling fan is investigated experimentally and analyzed within the framework of rotor-stator interaction noise using point source formulation. The fan is 9 cm in rotor casing diameter and its design speed is 3000 rpm. The main noise sources are found and quantified; they are (a) the inlet flow distortion caused by the sharp edges of the incomplete bellmouth due to the square outer framework, (b) the interaction of rotor blades with the downstream struts which hold the motor, and (c) the extra size of one strut carrying electrical wiring. Methods are devised to extract the rotor-strut interaction noise, (b) and (c), radiated by the component forces of drag and thrust at the leading and higher order spinning pressure modes, as well as the leading edge noise generated by (a). By re-installing the original fan rotor in various casings, the noises radiated by the three features of the original fan are separated, and details of the directivity are interpreted. It is found that the inlet flow distortion and the unequal set of four struts make about the same amount of noise. Their corrections show a potential of around 10-dB sound power reduction.
Acoustic and spectral characteristics of young children’s fricative productions: A developmental perspective
Authors: Nissen Shawn L. , Fox Robert Allen
Published: October 2005

Scientists have made great strides toward understanding the mechanisms of speech production and perception. However, the complex relationships between the acoustic structures of speech and the resulting psychological percepts have yet to be fully and adequately explained, especially in speech produced by younger children. Thus, this study examined the acoustic structure of voiceless fricatives (∕f, θ, s, ʃ∕) produced by adults and typically developing children from 3to6years of age in terms of multiple acoustic parameters (durations, normalized amplitude, spectral slope, and spectral moments). It was found that the acoustic parameters of spectral slope and variance (commonly excluded from previous studies of child speech) were important acoustic parameters in the differentiation and classification of the voiceless fricatives, with spectral variance being the only measure to separate all four places of articulation. It was further shown that the sibilant contrast between ∕s∕ and ∕ʃ∕ was less distinguished in children than adults, characterized by a dramatic change in several spectral parameters at approximately five years of age. Discriminant analysis revealed evidence that classification models based on adult data were sensitive to these spectral differences in the five-year-old age group.
Injection of ac current into scala media alters the sound pressure at the tympanic membrane: Variations with electrical stimulus parameters
Authors: Mountain D. C. , Hubbard A. E.
Published: October 2005

The sound pressure near the tympanic membrane of gerbils was measured using a probe tube microphone during the injection of ac current into the basal turn of the cochlea. Electrical currents of up to 5 μA with frequencies ranging from 25 to 1500 Hz were used. The sound pressure signal was sampled, averaged, and stored by computer for subsequent Fourier analysis. The sound pressure is modulated as much as 1% by the electrical current. The modulation is proportional to current level and is a low-pass function of electrical frequency with a time constant of approximately 1 ms. The modulation disappears in dead animals and is not observed if the current injection electrode is not in scala media. In addition, the modulation can vary with time and often deteriates in long experiments. Our data may be the result of changes in stiffness of the haircell stereocilia, mediated by changes in haircell membrane potential.
High-resolution filter bank for speech analysis
Authors: Linggard R. , Black N. D.
Published: October 2005

A digital filter bank is described which has been designed to be an approximate model of the basilar membrane. Designed from analog prototypes using the bilinear transformation, the bank consists of 145 4th-order bandpass filters on a log frequency scale with bandwidths according to physiologically determined values. The short-time, wide-band spectra available from this filter bank have been processed to give relatively accurate indications of periodic pitch. An essential part of this processing is the enhancement of pitch harmonics before using the spectral information in a matching procedure to measure pitch. This paper discusses its physiological plausibility. Some results of pitch tracking in continuous speech are given.
A further test of a two-formant model
Authors: Bladon Anthony , Ladefoged Peter
Published: October 2005

The concept of F2′ as an upward weighting of F2 to allow for the perceptual contribution of upper formants [F2′ being calculated according to the formula proposed by R. A. W. Bladon and G. Fant (Quarterly Progress and Status Report, R. I. T. Stockholm, 1978–1, 1–8)] is reviewed critically in the light of the demonstration that vowels exist which sound different although they have the same F1 and F2′. A procedure for generating vocal tract shapes from such formant frequencies yielded shapes which correspond to humanly realizable vowels and yet which are markedly different shapes. Three pairs of vowels synthesized with these formant frequencies were judged by listeners to be auditorily as different as the pair [i-e] which is phonemically contrastive in many languages. It is concluded that this two-dimensional model of vowel perception is inadequate, at least as currently formulated.
Alterations in bilateral tinnitus following an exposure to a pure tone
Authors: Young I. M. , Lowry L. D.
Published: October 2005

In a subject with bilateral tinnitus of a pitch 10 000 Hz, loudness 50–55 dB SPL, left ear was exposed to a steady tone, 500 Hz, at 121 dB SPL for 21 min. Immediately following cessation of stimulation, tinnitus had completely disappeared from stimulated ear and was heard in the opposite nonstimulated right ear. Three hours after stimulation, tinnitus was heard in the left ear as mixture of multiple frequencies superimposed upon broadband noise and/or low-pass filtered noise. Twenty-four hours after stimulation, tinnitus pitch changed to 3260 Hz, 2 days later 5100 Hz, 3 days later 8310 Hz, and 1 week later returned to original pitch 10 000 Hz and stayed on to date. In the nonstimulated right ear, however, immediately after cessation of stimulation, tinnitus pitch was 6700–8000 Hz for 48 h. Thereafter, tinnitus has been fluctuating from 8000–9000 Hz to a narrow-band noise centered around 7986 Hz with a bandwidth of 2710 Hz and vice versa. The tinnitus never returned to previous pre-exposure pitch of 10 000 until 4 weeks after exposure. There was an apparent difference of recovery process between two ears. Factors influencing tinnitus in two ears were discussed.
Pitch perception in low-frequency hearing-loss listeners
Authors: Turner C. W. , Nelson D. A. , Burns E. M.
Published: October 2005

Pitch perception for pure tones was investigated in a group of low-frequency sensorineural hearing-loss listeners. Pitch judgments and psychophysical tuning curves (PTCs) were obtained from each listener. Two distinct types of PTCs were observed. A few listeners demonstrated “mistuned” PTCs (considerable masking of low-frequency probes by maskers of much higher frequency), while the remainder of the listeners demonstrated “normally tuned” PTCs (no masking of low-frequency probes by maskers of much higher frequency). The measures of pitch perception employed were: (1) binaural pure-tone pitch matching in listeners with unilateral hearing loss, and (2) octave judgments in listeners with bilateral hearing loss. The individual listeners' pitch judgments failed to distinguish between the “mistuned” and “normally tuned” PTC groups. The results suggest that “mistuned” PTCs do not reflect an abnormal place of stimulation along the basilar membrane, or that pitch perception for tones of 500 Hz and less is not encoded by the place of cochlear stimulation. [Work supported by NIH.]
Auditory masking effects on lingual vibrotactile thresholds as a function of age
Authors: Fucci Donald , Petrosino Linda , Robey Randall R.
Published: October 2005

Auditory masking effects on lingual vibrotactile thresholds were examined across three groups of ten subjects each. The first group consisted of children 13 years of age or younger, the second group consisted of young college age adults, and the third group consisted of elderly individuals 66 years of age or older. Lingual vibrotactile thresholds were obtained from each group at a frequency of 250 Hz, under experimental conditions consisting of no-masking, narrow-band masking, and wide-band masking. Results showed statistically significant threshold differences between the elderly group and the other groups for all three experimental conditions. A difference was also detected between experimental conditions when an overall statistical analysis was performed, but this difference disappeared under more stringent post-hoc examination. The elderly group's most sensitive thresholds occurred under the no-masking condition, and masking had no noticeable effect on the lingual vibrotactile thresholds of the young adults and children. Obtained results are compatible with the current literature on aging and support the recommendation that auditory masking be eliminated from the lingual vibrotactile testing paradigm.
The acoustic reflex latency in the aging ear
Authors: Spence Scott W. , Kisiel Dennis , Catts Hugh
Published: October 2005

The latency of the acoustic reflex was measured for a group of normal hearing young adults (ages 20–29) and two groups of normal hearing elderly adults (ages 50–69). One latency parameter, the initial impedance change to maximum amplitude, was determined through computer assisted, contralateral recordings of the stapedial reflex. Five consecutive presentations of a 2000-Hz tone (10-ms rise-fall time, 250-ms duration and a 2-s inter-stimulus interval) were used as activating stimuli. Graphic recordings of the acoustic reflex were made at three intensity levels (reflex threshold, +10 dB SL, and +20 dB SL) for the right and left ears of each subject. Preliminary analysis revealed similar latencies for all groups. Stapedial contraction time was less variable at intensity levels above reflex threshold. The latency-intensity function is discussed in relation to subject age.
Self-polarized measurement microphones
Authors: Rasmussen Gunnar
Published: October 2005

Electret microphones are capacitive transducers characterized by having a permanent prepolarization between the two capacitive electrodes. The electret microphones may use the prepolarized material either as diaphragm material or as a coating of the fixed electrode. For measurement microphones it is important in order to fulfill standardized requirements to use the most stable configuration. The standards require good long stability, low and well-defined equivalent volume, low dependency on ambient pressure, low temperature coefficient, and stable performance in order to give reliable measured results. This is achieved in the coated back plate configuration utilizing the electret material for prepolarization only. The diaphragm may then still be of high quality and known performance. Practical experience with prepolarized electret back plate covered microphones in field use over the later years will be reported.
Electroacoustics in an audio-teleconferencing bridge
Authors: Braun Daryl
Published: October 2005

In audio teleconferencing, the bridge which ties together the lines used by the conference participants is considered the backbone of the teleconference. Its grade of performance can make or break the telemeeting. The preferred speech and hearing sound levels determine the ultimate input and output parameters of an audio-teleconferencing system. The terminal and the network translate those parameters into others for transmit and receive at the bridge. The latter has then to tie together the conference lines, normalizing all signals to a certain level, without adding the line noises. Switching between lines should be fast enough to provide normal interaction. Attempts to answer or interrupt should also be heard for the same reason. Other logistic functions such as automatic call-in (meet-me), manual add-on, signaling, security, ride-conferences, operator control, conference recording or tape-playback, etc. must also be accommodated. This paper describes how these requirements have been fulfilled in the design concept as well as the performance of the Darome bridges (the “Co-Converters”). A demonstration will be available for those interested.
Responses of primary auditory fibers to transient sounds
Authors: Geisler C. Daniel , Sinex Donal G.
Published: October 2005

Responses of primary auditory fibers to clicks, short tone bursts, FM sweeps and consonant-vowel syllables were obtained in the anesthetized cat. Tone-burst responses depend on the fiber's characteristic frequency (CF). Fibers of high CF (above 10 kHz) responded to 2-ms bursts with practically steady-state frequency selectivity. Fibers with low CF (below 1 kHz) needed 10-ms bursts to approach steady-state rate selectivity. However, temporal encoding of the stimulus frequency was established in low-CF fibers within 5 ms. Rapid establishment of temporal encoding is also characteristic of responses to the consonant-vowel sounds: response patterns in successive 8-ms epochs accurately reflected formant frequencies in those epochs. Responses to FM sweeps essentially encoded instantaneous stimulus frequency. The basic characteristics of click responses for any fiber were generally predictable by a minimum-phase model derived from its threshold-response curve. This model also generated realistic tone-burst responses. Our evidence indicates that each primary fiber is a short-term spectral analyzer whose transient behavior approximates that of a filter having its threshold-response curve. [Work supported by NIH.]
Temporal characteristics of repeated utterances
Authors: Linville Raymond N. , Folkins John W.
Published: October 2005

The purpose of this study was to develop a quantitative description of the temporal characteristics of repeated utterances. Movements of the lower lip, jaw and tongue tip were obtained during the production of /dɑb/, /pɑt/, /ɑb/, /bɑ/, /ib/, and /bi/ with strain gauge and cineradiographic techniques. Four subjects repeated each syllable in synchrony with clicks presented at 2.5, 3.0, 3.5, 4.0, and 4.5 Hz. A second condition using a 10-mm bite block was also employed to compare with jaw-free productions. Additionally, cycle duration was defined as the period of time between successive opening movements. Each movement cycle was divided into four components: opening movement, open posture, closing movement, and closed posture. A multivariate regression design was used to show that as cycle duration varied there were temporal interactions between open and closed postures, and between opening and closing movements. Specifically, regression coefficients of open and closed postures demonstrated reciprocal relations as a function of cycle duration. Similiar results were found for the bite-block condition. Data will be discussed with respect to models of speech production. [Work supported by NINCDS and NIDR.]
Investigation of forward sound field amplitude and phase fluctuations by boundary perturbations in a normal-mode duct
Authors: Layton Michael R.
Published: October 2005

A physical model of a shallow-water duct has been constructed with a 5-cm (4λ) isovelocity water layer overlying a 10-cm homogeneous sand bottom. Using a projector operating cw at 100 kHz, a propagating normal-mode pressure distribution consisting primarily of the lowest-order mode was established in the duct. A pair of small hydrophones were then positioned in the water layer at identical range and depth, with a horizontal separation between them on the order of 1.5 cm (one wavelength). Prior to investigating the effect of a small perturbation either on the water surface or at the water-sand boundary, the difference between the received signals from each hydrophone was nulled using electronic means. The differential signal behavior was then examined for a variety of experimental conditions, which included surface roughness, bottom roughness, receiver depth, receiver range (from projector), and receiver separation. [Work supported by ONR and DARPA.]
Three-dimensional, farfield measurements of a Gaussian profile ultrasonic transducer
Authors: Claus Richard O. , Zerwekh Paul S.
Published: October 2005

An ultrasonic transducer has been constructed using a concentric array of annular metallic electrodes on a thin circular piezoelectric substrate. The transducer is driven through an impedance matching and weighting network to produce an electric field within the substrate that is an optimized piecewise linear approximation to a two-dimensional Gaussian function [P.S. Zerwekh and R. O. Claus, IEEE 1981 Ultrason. Symp., Chicago, IL]. In this paper, the calculated farfield Gaussian amplitude distribution is presented and compared to experimental data measured using a microprocessor-controlled automatic scanning system at a distance of 500 wavelengths in a water tank. This data is also compared with similar analytical and experimental results obtained for a circular piston transducer having only one active surface electrode. Applications of the transducer in acousto-optical modulation systems and in the ultrasonic inspection of metallic surfaces is discussed. [Work partially supported by NSF and NASA.]
Sound radiation from an axisymmetric radiator in an infinite baffle
Authors: Suzuki Hideo , Tichy Jiri
Published: October 2005

A method that can be applied to the radiation problem of a convex or a concave radiator in an infinite baffle is described. This method utilizes the least-square-error method, and allows the radiator to take almost any kind of axisymmetric shape even though the accuracy of the result depends on the shape. The frequency responses of the on-axis sound pressure are calculated for three cases of the radiator shape, a convex dome, a concave dome, and a combination of a truncated concave cone and a convex dome at the center. The accuracy is confirmed by comparing the results obtained by the present method with those obtained by previous methods [Hideo Suzuki and Jiri Tichy, J. Acoust. Soc. Am. 69, 41–49 (1981)]. Three error indexes are suggested for an estimation of the accuracy of the results.
Standards and measurement of rail, road, and off-road roughness
Authors: Barton J. C.
Published: October 2005

The application of surface roughness descriptions to vehicle roadways is reviewed in general terms. Vehicle roadways include railroad track, streets and roads (road vehicles), and off-road terrain (agricultural tractors, earthmoving machines, etc.). The parameters of interest, measurement and analysis considerations, related standards, and the practical use of the data are discussed. The wavelengths of interest range from a few inches to a few thousand feet. The amplitudes of interest range from fractions of an inch to 10 or 12 ft. The application of fundamental descriptions of surface roughness to vehicle vibration theory illustrates and quantifies what we all observe, that the roadway roughness has much more influence on vehicle vibration than does the vehicle suspension. It is not practical to offset poor or deteriorated roads with improved suspension systems.
Level crossing statistics and Hausdorff-Besicovitch similarity dimension of generalized rough surfaces
Authors: Moritz Elan , Kenton Arthur Craig
Published: October 2005

Generalized rough surfaces can exhibit a rich variety of relief that cannot be easily described as either periodic or Gaussian. For such surfaces, one can explore the spatial distribution per unit length of occurrence of the mean height (=0 by definition), the rms heights, or the crossing of the relief with a chosen level. An extension of this concept is also possible with joint probability distribution characterization of the distribution of successive level crossing known as Palm distributions. Evaluation of these measures for some test functions and stochastically generated surface relief is presented and the benefits of their use is contrasted with conventional statistical and correlation function techniques. Surfaces that contain a possible infinite hierarchy of scales, e.g., fractal surfaces, are shown to best be characterized by a parameter known as the Hausdorff-Besicovitch similarity (HBS) dimension. The use of this parameter in describing generalized rough surfaces possessing self-similar characteristics or multiple scales of roughness is described and the reflection characteristics of such surfaces in optical and acoustical applications are discussed.
Instructional uses of linear filters and transmission lines
Authors: Savage William R.
Published: October 2005

G. W. Stewart was a pioneer in the use of the analogy between lumped parameter electrical circuit theory and acoustical transmission lines and filters. He published a series of papers based on the work of his students and his own studies. Recently about half of these filters were discovered in a storage room at The University of Iowa. The filters were fabricated from standard size brass and copper tubing. Some of the filters will be displayed and demonstrated with modern drivers and detectors. Similar devices could be constructed and used for lecture demonstration, laboratories, and student research.
Three-tone suppression
Authors: Javel E. , McGee J. , Farley G. R. , Gorga M. P. , Walsh E. J.
Published: October 2005

Responses of single neurons in the anteroventral cochlear nucleus were recorded from anesthetized cats as the intensities of three fixed-frequency pure tones were systematically varied. One tone, the excitor, was sent to the neuron's CF. Two-tone suppression of responses to the excitor tone was then studied for a suppressor tone above CF, and then for a suppressor tone below CF. Suppression magnitude was taken as the parallel shift (in dB) of the response-versus-intensity function for the excitor tone caused by introducing the suppressor tone at fixed intensities. When all of the two-tone effects had been studied, three-tone responses were collected until every relevant intensity combination had been explored in 5-dB steps. Adding the third tone produced a linear increase in suppression magnitude over either two-tone condition. The total amount of suppression in the three-tone case was equal to the sum of the two-tone suppressive effects. Additivity of suppression was the same for both discharge rate and discharge synchronization. [Work supported by NINCDS grant NS-14880.]
Predicting speech intelligibility in rooms
Authors: Bradley J. S.
Published: October 2005

The pioneering work of Lochner and Berger [e.g., J. Sound Vib. 1(4), 426–454 (1964)] has provided a basis for measuring and calculating speech intelligibility in rooms in terms of a ratio of useful early sound to detrimental late arriving sound and background noise. In the present work their results are used in an image sources computer model to predict speech intelligibility in rooms. The calculation procedure is discussed and the influence on speech intelligibility of room geometry, room surface sound absorption properties, and background noise levels are investigated. Comparisons are made with speech intelligibility calculations based on the modulation transfer function approach.
A cross-language study of velar coarticulation
Authors: Henderson Janette B. , Honda Kiyoshi , Bell-Berti Fredericka , Prakash Dixit R.
Published: October 2005

In English, velar elevation is greater for close than for open vowels and is also affected by adjacent consonants. In this study, we collected data on Hindi, a language in which the oral-nasal contrast is phonologically relevant for both vowels and consonants, in addition to English, in which the oral-nasal contrast for vowels is generally considered irrelevant. We investigated the effects of vowel height and consonantal environment on the degree of velar elevation and velopharyngeal opening using two procedures. The first involved simultaneous high-speed films of velar height and electromyographic signals from the levator palatini muscle, and the second, high-speed films of velopharyngeal opening and electromyographic signals from both the levator palatini and superior pharyngeal constrictor muscles. Data were collected for a series of vowels varying from close to open in four consonantal environments in both languages, and for an additional series of nasal vowels in Hindi. Comparative data on velar coarticulation in these two languages and in both nasal and oral vowels will be presented. [Work supported by NINCDS and BRS.]
Phonetic differences in glottalic consonants
Authors: Lindau Mona
Published: October 2005

Data on glottalic consonants in a number of languages were examined. Data on implosives come from Hausa, Degema, and three Eastern Ijo languages, all spoken in Nigeria. Ejective data come from Hausa and Navaho. The implosives in Degema and the Ijo languages show a strong positive correlation (r = 0.9; p = 0.025) between the closure duration and the intensity of implosion. However, Hausa implosives do not follow this correlation in that they have a high intensity implosion with a relatively brief closure duration. This is attributed to the fact that Hausa implosives are also laryngealized, and the resulting lower airflow into the vocal tract makes it possible to have a more efficient implosion in Hausa. Due to the different phonation type the implosive mechanism is thus considerably different in Hausa than in the other languages. The ejectives in Hausa and Navaho differed along several parameters: total duration, ratio closure duration/open interval, and phonation type in the vowel onset. Thus what appears to be the same sound nevertheless has to be described in different ways for different languages. [This work was supported by NSF.]
Sound attenuation due to wind-generated bubbles in the ocean
Authors: Bruno Daniel R. O. , Novarini Jorge C.
Published: October 2005

The effects of near-surface bubbles on refraction and attenuation in sound propagation in the ocean are calculated from a semi-empirical model of bubble-size spectrum based on photographic data [B. D. Johnson and R. C. Cooke, J. Geophys. Res. 84, 3761–3766 (1979)]. The attenuation rates are calculated by numerical integration over the entire bubble spectrum. By fitting the numerical results simple expressions are obtained which allow the computation, in hand-held calculators, of the energy losses in surface duct propagation and two-way attenuation in vertical paths. The study has been carried out at frequencies of interest for active and fish-finding sonars, and for wind speeds up to 30 knots.
Control of impact pile driving noise and alternative techniques
Authors: Gill Harjodh S.
Published: October 2005

In recent years there has been a concerted effort by civil engineering contractors and some manufacturers to reduce noise from impact pile drivers and in some cases to employ alternative piling techniques. These alternative techniques range from hydraulic, vibratory, sonic, and bored piling techniques. This paper outlines the results of a study, primarily conducted in the United Kingdom, of noise levels, spectra and waveform shapes from a range of pile driving devices which were either adapted or designed specifically to produce noise levels below those normally expected from conventional impact pile drivers and these are also included for comparison purposes. In addition, the paper will outline briefly the noise reduction techniques employed by some manufacturers and will present the results of the assessment of various noise control techniques. Alternative piling techniques will also be discussed together with measured data. This study indicates that careful consideration of noise control and alternative piling techniques can generate approximately 20 to 40 dBA lower equivalent sound levels than those generated by the untreated conventional impact piling machines at equivalent distances, these reduced noise levels being equal to or less than those produced by other construction site noise sources.
A preliminary comparison between the SR-3 propeller noise in flight and in a wind tunnel
Authors: Dittmar James H. , Lasagna Paul L.
Published: October 2005

The noise generated by supersonic-tip-speed propellers is a possible cabin environment problem for future airplanes powered by these propellers. Models of these types of propellers were previously tested for acoustics in the Lewis 8-by-6-foot wind tunnel. One of these propeller models, SR-3, has now been tested in flight on the Dryden JetStar airplane and preliminary noise data have been obtained. Preliminary comparisons of the maximum blade passing tone variation with helical tip Mach number taken in flight with those taken in the tunnel showed good agreement when corrected to the same test conditions. This indicated that the wind tunnel is a viable location for measuring the noise of these propeller models. Comparisons of the directivities at 0.6 and 0.7 axial Mach number showed reasonable agreement. At 0.7 and 0.8 axial Mach number the tunnel directivity fell off quicker towards the front than did the airplane data. A possible explanation for this is boundary layer refraction which could be different in the wind tunnel than in flight. This may indicate that some corrections should be applied to both the airplane and wind tunnel data at the forward angles. At the peak noise angle the boundary layer refraction does not appear to be significant and no correction appears necessary.
Features of an underwater explosion record as function of depth
Authors: Epstein David
Published: October 2005

The waveform from a deep-fired underwater explosion bears only superficial resemblance to its shallow-fired counterpart. The latter may be characterized as a highly nonlinear pulsation, while the former tends to look more like a linear damped oscillation. In this report, we expand upon the results given in an earlier paper. [J. Acoust. Soc. Am. Suppl. 1 69, S97 (1981)]. Calculations have been performed which yield theoretical values for features of the explosion waveform, such as the bubble pulse and first negative pulse pressure, as function of detonation depth. These calculations support the conclusion that the bubble pulse amplitude increases slowly with depth. The negative pulse, however, increases at a much more rapid rate and may even overtake the bubble pulse if the ambient pressure is sufficiently high! Estimates of the power law dependence of the features are presented.
Evoked response correlates of auditory pathway maturation
Authors: Walsh E. J. , Javel E. , McGee J.
Published: October 2005

There exist certain features in the electrophysiological development of auditory responses that behave consistently across mammalian species. Some of these are the decline of response latency with age, the paradoxical maturation of frequency sensitivity, the rapid maturation of response threshold, and the growth of response amplitude during the neonatal and early postnatal period. Our work has focused on the development of the auditory brainstem response (ABR) in unanesthetized kittens. Using free-field click stimuli, we have discerned two developmental stages. The first or early stage begins at about 10 days postpartum, coincident with the appearance of ABRs at high intensities. It is characterized by ABR wave latencies that decline rapidly and ABR wave amplitudes that increase rapidly with age. These behave more-or-less linearly. The second or later stage begins at about 20 days of age. ABR wave latencies mature less rapidly during this stage, reaching asymptotic values at about 60 days of age for wave V. These behave exponentially. ABR waves originating from higher auditory brainstem nuclei mature more slowly than waves originating from more peripheral nuclei. ABR responses to tone pips also develop in two stages, with development of low-frequency sensitivity lagging behind development of middle- and high-frequency sensitivity. In kittens, cortical-evoked responses develop in parallel with ABR responses, but their measurement is considerably less reliable. When the relative rates of maturation are taken into account, it is seen that the same sequence of events occurs in human infants, except that the early stage of ABR development happens prenatally. [Work supported by grant NS-14880 from NINCDS and by a biomedical research supplement grant from NIH.]
Computer-controlled x-ray microbeam—Method, history, and sample results
Authors: Fugimura Osamu
Published: October 2005

A computer-controlled x-ray microbeam system was proposed in the early 60's by the author, and a pilot system was implemented by him and his colleagues at the University of Tokyo in 1968 [O. Fujimura et al., DECUS Proc. 279–283 (1969); O. Fujimura, et al., Comput. Biol. Med. 31, 371–384 (1973)], being supported in part by NIH (research grant NB07233). With the aid of the University and the Ministry of Education, Japan, a system for exploratory use in articulatory studies was completed in 1974 [S. Kiritani, et al., J. Acoust. Soc. Am. 57, 1516–1520 (1975)]. The system is currently in operation at the University of Tokyo, and a few groups in Japan and the U.S. are involved in conducting research using this sytem. The method will be described and some preliminary results of representative experiments, using data analysis software at Bell Laboratories, will be presented. [Supported in part by NINCDS grant.]
Scientific rationale for the x-ray microbeam and its intended capabilities for shared use
Authors: Abbs James H.
Published: October 2005

In the last two decades we have seen dramatic progress in our understanding of speech physiology and speech acoustics, yielding numerous models and hypotheses concerning movement correlates of speech acoustics, speech muscle actions and potential underlying nervous control. Increasingly, however, it is apparent that speech production, when observed within or across subjects shows substantial variability, a phenomenon that in some cases illustrates the limitations of our models and in other cases reveals potentially important system characteristics, e.g., quantal articulatory discontinuities, motor equivalence coordination, etc. Indeed, many current notions concerning speech production have only been tested except for limited circumstances. In part this is due to an inability to obtain large sample of speech movement data, unobtrusively and safely. Hence, the mission of this national shared x-ray microbeam facility is to provide needed speech movement data to discover and extend principles of speech production behavior. The general capabilities of the intended facility in relation to this goal will be discussed from a user's perspective. [Research supported by NINCDS grant.]
A new microbeam facility for speech research
Authors: Thompson Murray
Published: October 2005

The x-ray microbeam facility being designed and constructed at the University of Wisconsin has been based, in large part, upon the prototype University of Tokyo system. However, in an attempt to improve the performance over the pioneering work of Dr. Fujimura and his co-workers, a number of design modifications have been incorporated. These include (1) a substantially higher electron beam acceleration voltage, hence generating x rays with improved capabilities for imaging through obstacles such as dental fillings, (2) generation of x rays in the forward direction, reducing the complexity and improving the performance of the x-ray beam deflection system, (3) employing a new geometry for the electron beam/x-ray paths for better position accuracy, (4) an x-ray detector that is segmented for reduction of undesirable photon scatter effects, (5) implementation of a pattern recognition/background subtraction scheme, in digitial microcode format, to minimize pellet mistracking and improve resolution even under conditions such as with dental fillings, etc., and (6) allowance for variable exposure on each sample point so as to minimize the already small x-ray dose. These and related design-implementation features of the shared x-ray microbeam facility will be discussed. [Supported in part by NINCDS grant.]