bluuebunny/crossref_metadata_2025 huggingface dataset:
The Physiological Role of Androgens in Penile Erection: Regulation of Corpus Cavernosum Structure and Function
Authors: Traish Abdulmaged , Kim Noel
Published: October 2005

Traish A, Kim N. The physiological role of androgens in penile erection: regulation of corpus cavernosum structure and function. J Sex Med 2005;2:759–770

It is generally accepted that androgens are critical for development, growth, and maintenance of penile erectile tissue. However, their role in erectile function, especially in humans, remains controversial. Clinical and preclinical studies have suggested that venoocclusion is modulated by the tone of the vascular smooth muscle of the resistance arteries and the cavernosal tissue and a balance between trabecular smooth muscle content and connective tissue matrix. In men with erectile dysfunction, venous leakage is thought to be a common condition among nonresponders to medical management and is attributed to penile smooth muscle atrophy. In the animal model, androgen deprivation produces penile tissue atrophy concomitant with alterations in dorsal nerve structure, endothelial morphology, reduction in trabecular smooth muscle content, and increased deposition of extracellular matrix. Further, androgen deprivation results in accumulation of fat-containing cells (adipocytes) in the subtunical region of the corpus cavernosum. Androgen deficiency diminishes protein expression and enzymatic activity of nitric oxide synthases (eNOS and nNOS) and phosphodiesterase type 5 (PDE5). The androgen-dependent loss of erectile response is restored by androgen administration but not by administration of PDE5 inhibitors alone. These data suggest that androgens regulate trabecular smooth muscle growth and connective tissue protein synthesis in the corpus cavernosum. Further, androgens may stimulate differentiation of progenitor cells into smooth muscle cells and inhibit their differentiation into adipocytes. Thus, we conclude that androgens exert a direct effect on penile tissue to maintain erectile function and that androgen-deficiency produces a metabolic and structural imbalance in the corpus cavernosum, resulting in venous leakage and erectile dysfunction.
Host range, vector relationships and sequence comparison of a begomovirus infecting hibiscus in India
Authors: Rajeshwari R. , Reddy R.V.C. , Maruthi M.N. , Colvin J. , Seal S.E. , Muniyappa V.
Published: October 2005

Hibiscus leaf curl disease (HLCuD) occurs widely in India. Infected hibiscus plants show vein thickening, upward curling of leaves and enations on the abaxial leaf surface, reduction in leaf size and stunting. The commonly‐occurring weeds (Ageratum conyzoides, Croton bonplandianum and Euphorbia geniculata), Nicotiana benthamiana, Nicotiana glutinosa and Nicotiana tabacum (var. Samsun, Xanthi), cotton and tomato were shown to be susceptible to HLCuD. One of the four species of hibiscus (Hibiscus rosa‐sinensis) and 75 of the 101 commercial hybrids/varieties grown in the Bangalore area of southern India were also susceptible. Two virus isolates associated with HLCuD from Bangalore, South India (Ban), and Bhubaneswar, North India (Bhu), were detected serologically and by PCR‐mediated amplification of virus genomes. The isolates were characterised by sequencing a fragment of DNA‐A component (1288 nucleotides) and an associated satellite DNA molecule of 682 nucleotides. Phylogenetic analyses of these DNA‐A sequences clustered them with Old World cotton‐infecting begomoviruses and closest to Cotton leaf curl Multan virus (CLCuMV) at 95–97% DNA‐A nucleotide identities. The 682‐nucleotide satellite DNA molecules associated with the HLCuD samples Ban and Bhu shared 96.9% sequence identity with each other and maximum identity (93.1–93.9% over positions 158–682) with ∼1350‐nucleotide DNA‐β satellite molecules associated with cotton leaf curl disease in Pakistan and India (accession nos AJ298903, AJ316038). HLCuD in India, therefore, appears to be associated with strains of CLCuMV, a cotton‐infecting begomovirus from Pakistan, which is transmitted in a persistent manner by Bemisia tabaci.
Morphological and molecular characterisation of Puccinia lagenophorae, now present in central North America
Authors: Littlefield L.J. , Marek S.M. , Tyrl R.J. , Winkelman K.S.
Published: October 2005

In June 2004, a rust fungus not previously reported for Oklahoma was found occurring naturally on the weed, common groundsel, Senecio vulgaris, in pots in a commercial container nursery in northeastern Oklahoma. Host symptoms and morphology of teliospores and aeciospores of the fungus were consistent with those of Puccinia lagenophorae, a recent introduction into North America that has, as yet, been reported only on the East and West Coasts of the USA. This is the first report of the rust in central regions of North America. The rust is believed to be native to Australia and New Zealand and subsequently reported in most continents on numerous species and genera of the Asteraceae. Some authors in Europe consider the rust on Bellis as different from the one on Senecio, naming it Puccinia distincta. Our ITS1‐5.8S‐ITS2 ribosomal DNA sequence data, however, show homology with P. distincta sequences from Europe, indicating there is only one morphologically‐variable polyphagous species. Presumably, the rust was introduced into Oklahoma on infected plants from the West Coast of the USA, the source of most plant material in the commercial nursery where it was found. The rust is potentially important on several ornamental Asteraceae in North America as it has become in Europe, where it spreads rapidly throughout that continent following its introduction there in the early 1960s.
Acoustic generation in piezoelectric materials by microwave excitation
Authors: Hadj Henni A. R. , Bacon C. , Hosten B.
Published: October 2005

As an application of ultrasound generation by microwave excitation, a study of piezoelectric material behavior is presented. Piezoelectric bars excited electrically or by microwave irradiation give different resonance frequencies. Piezoelectric materials are subject to a stiffening phenomenon (variation of the apparent Young’s modulus) when the electrical boundary conditions change and, as a result, when the material is dynamically excited, a modification of the natural resonance frequencies occurs. A one-dimensional model, to predict the acoustic waves generated in piezoelectric materials by an unspecified excitation source, is presented and compared to experimental results. This model is used as a nondestructive evaluation method to characterize piezoelectric samples and to highlight the thermoelastic origin of the acoustic generation when the piezoelectric materials are excited by pulsed microwaves.
Acoustic radiation by vortex induced flexible wall vibration
Authors: Tang S. K. , Leung R. C. K. , So R. M. C. , Lam K. M.
Published: October 2005

Sound radiation due to unsteady interaction between an inviscid vortex (which models a turbulent eddy) and a finite length flexible boundary in a two-dimensional space is studied using potential theory and the matched asymptotic expansion technique. The Mach number of the vortex propagation is kept below 0.15. Results suggest that the monopole field created by the volumetric flow induced by the vibrating flexible boundary dominates the overall acoustic power radiation. The longitudinal dipole directly due to the transverse vortex acceleration is only important when the vortex is moving over the flexible boundary. The longitudinal dipole resulting from the boundary vibration gains slightly in importance in the strong vortex case, but the corresponding transverse dipole remains negligible for the cases considered in the present study. The two longitudinal dipoles give rise to biased radiation directivities on both sides of the flexible boundary.
Beam-tracing model for predicting sound fields in rooms with multilayer bounding surfaces
Authors: Wareing Andrew , Hodgson Murray
Published: October 2005

This paper presents the development of a wave-based room-prediction model for predicting steady-state sound fields in empty rooms with specularly reflecting, multilayer surfaces. A triangular beam-tracing model with phase, and a transfer-matrix approach to model the surfaces, were involved. Room surfaces were modeled as multilayers of fluid, solid, or porous materials. Biot theory was used in the transfer-matrix formulation of the porous layer. The new model consisted of the transfer-matrix model integrated into the beam-tracing algorithm. The transfer-matrix model was validated by comparing predictions with those by theory, and with experiment. The test surfaces were a glass plate, double drywall panels, double steel panels, a carpeted floor, and a suspended-acoustical ceiling. The beam-tracing model was validated in the cases of three idealized room configurations—a small office, a corridor, and a small industrial workroom—with simple boundary conditions. The number of beams, the reflection order, and the frequency resolution required to obtain accurate results were investigated. Beam-tracing predictions were compared with those by a method-of-images model with phase. The model will be used to study sound fields in rooms with local- or extended-reaction multilayer surfaces.
Characterization of a small moving-magnet electrodynamic linear motor
Authors: Liu Jin , Garrett Steven
Published: October 2005

The mechanical and electrodynamic parameters of a small, potentially inexpensive, moving-magnet electrodynamic linear motor are determined experimentally. Employing the formalism introduced by Wakeland, these parameters are used to predict the electromechanical efficiency of the motor. The transduction coefficient, Bl, was observed to be a function of position. But as shown in the paper, the variation in Bl with position has a smaller effect on the driver’s output power because Bl is largest around the equilibrium position, where the piston velocity is also largest. By mechanical colinear joining of the armatures of two such motors, an electrodynamic load (dynamometer) is created to measure the efficiency as a function of energy dissipated in the dynamometer. The measured efficiencies are shown to be in good agreement with the predictions if a position-averaged effective transduction coefficient is introduced. Based on these results, this linear motor is judged to be an attractive power source in small electrically driven thermoacoustic refrigerator applications.
Energy pass bands in a ribbed cylindrical shell with periodic asymmetries
Authors: Marcus Martin H. , Houston Brian H.
Published: October 2005

The addition of periodically spaced structures to a cylindrical shell causes energy to propagate at additional wave numbers via a phenomenon known as Brillouin folding. As a result, a load representing one axial mode on a cylindrical shell with circumferentially spaced discontinuities, for example stringers, has distinct energy pass bands and stop bands. Similarly, an excitation representing one circumferential mode on a cylindrical shell with axially spaced discontinuities, for example ribs, also has distinct energy pass bands and stop bands. Discontinuities in both directions lead to energy pass bands when a point force is applied. In this paper, periodically spaced point masses in the axial and circumferential directions are added to a submerged, ribbed, finite cylindrical shell and analyzed via the finite element method. It is seen that Brillouin folding occurs and, in certain circumstances, the energy is split into pass bands and stop bands. For the frequency and circumferential modes where the subsonic energy is most narrowly focused in the axisymmetric shell, a distinct peak in radiated power occurs for the shell with point masses. The energy in this peak is about the same for several examples of different amounts of nonaxisymmetric mass.
Medial-olivocochlear-efferent inhibition of the first peak of auditory-nerve responses: Evidence for a new motion within the cochlea
Authors: Guinan John J. , Lin Tai , Cheng Holden
Published: October 2005

Despite the insights obtained from click responses, the effects of medial-olivocochlear (MOC) efferents on click responses from single-auditory-nerve (AN) fibers have not been reported. We recorded responses of cat single AN fibers to randomized click level series with and without electrical stimulation of MOC efferents. MOC stimulation inhibited (1) the whole response at low sound levels, (2) the decaying part of the response at all sound levels, and (3) the first peak of the response at moderate to high sound levels. The first two effects were expected from previous reports using tones and are consistent with a MOC-induced reduction of cochlear amplification. The inhibition of the AN first peak, which was strongest in the apex and middle of the cochlea, was unexpected because the first peak of the classic basilar-membrane (BM) traveling wave receives little or no amplification. In the cochlear base, the click data were ambiguous, but tone data showed particularly short group delays in the tail-frequency region that is strongly inhibited by MOC efferents. Overall, the data support the hypothesis that there is a motion that bends inner-hair-cell stereocilia and can be inhibited by MOC efferents, a motion that is present through most, or all, of the cochlea and for which there is no counterpart in the classic BM traveling wave.
Data reduction and resynthesis of connected solo passages using frequency, amplitude, and “brightness” detection and the nonlinear synthesis technique
Authors: Beauchamp James W.
Published: October 2005

Several computer algorithms have been developed for the analysis and synthesis of extended musical passages of several notes played by wind instruments. The technique includes inverse filtration, frequency detection, time-variant spectrum analysis, nonlinear analysis, amplitude and “brightness” (spectral centroid) matching, and nonlinear synthesis with forward filtering. Typically, a 20-to-1 data reduction is achieved while preserving most inflections of the original passage. Problems of selecting an appropriate inverse filter and other facets of the technique will be described. Further study of the derived frequency, amplitude, and “brightness” contours may lead to improved techniques for synthesis of connected passages by rule. The possibility for warping parameters before resynthesis may be useful as a tool for music composition.
Truncation and superposition effects in voice production
Authors: Fant Gunnar , Ananthapadmanabha T. V.
Published: October 2005

A time-domain analysis of format amplitudes has to cope with both truncation effects from excessive damping in the glottal open period and superposition effects, i.e., the carryover of residual formant oscillations from excitations in previous fundamental periods. There is also an interaction such that the magnitude of an excitation depends on the presence of F1 ripple from previous periods. These effects have been studied in live speech and with acoustic production models. Truncation is apparent in open back vowels at low F0 whereas superposition gains importance at high F0 only. The earlier observed tendency [G. Fant et al., J. Acoust. Soc. Am. 35, 1753–1761 (1963)] that when producing a sustained vowel with F0 gliding over a large range not only maximum F1 amplitudes but also maximum F2 amplitudes occur at integers of F1/F0 may in part be ascribed to the presence of F1 ripple in the transglottal pressure prior to closure.
Interferometric pulse-echo ultrasonic transducer system
Authors: Wade Janet C. , Claus Richard O.
Published: October 2005

The design, construction, and evaluation of a hybrid pulse-echo transducer system which uses an ultrasonic generating element and an optical detection technique is described. The transmitting transducer consists of a concentric aluminum-chromium ring pattern deposited on a 1.9-cm-diam circular x-cut quartz substrate with a circular 1.0-mm hole in the center. The rings are independently pulsed with a sequence of phased high-voltage signals in such a way that the ultrasonic waves resulting from the separate rings are focused at a controllable distance below the specimen surface. Energy in the focused wave reflected from this focus position is determined by the local reflection coefficient of the medium at the focal point. The reflected wave produces both normal and parallel components of particle displacement on the surface of the specimen at the location of the transmitting transducer and a wideband interferometric optical system insensitive to low-frequency background vibrations is used to measure the normal displacement through the hole. By processing the received signals for a range of ultrasonic transducer focal lengths, the system can be used to locate and size anomalies within solids and liquids. Applications in nondestructive evaluation and biomedical scanning are suggested. [Work partially supported by NSF and NASA.]
Prediction of underwater array performance from in-air measurements
Authors: Schafer Mark E. , Hughes W. Jack
Published: October 2005

A technique has been developed which accurately predicts the performance of underwater acoustic arrays prior to array construction. The method is based upon the measurement of lumped-parameter equivalent circuit values for each element in the array, using a procedure discussed in an accompanying paper. To test the prediction technique, the equivalent circuit values for a group of Tonpilz-type transducer elements were measured. From these values, the response of the elements could be predicted for any acoustic loading. Based on the predictions, a selection scheme was developed which minimized the effects of inter-element variability on array performance. Analysis of predicted beam patterns showed that the array designed by the selection method would have better sidelobe response than an array of the same elements, randomly selected. The measured transmitting and receiving characteristics of a test array, built using the selected elements, were compared to predictions made before the array was built. Results indicate that the technique is accurate over a wide frequency range and also indicate the necessity of including mutual impedance effects in the prediction process. [Work supported by NAVSEA.]
Speech processing and phonetic recognition strategies: What can be learned from auditory physiology and psychophysics?
Authors: Klatt Dennis H.
Published: October 2005

Speech scientists have held out the hope that discoveries in auditory physiology and psychophysics could be used to guide the design of mechanical speech processing devices. For example, from the speech scientist's point of view, an ideal peripheral auditory system for man might be one that would present to the central nervous system a representation of speech waveforms in which acoustic cues to phonetic contrasts were highlighted, while irrelevant acoustic details associated with changes in speech level, cross-speaker differences, and speech transmission channel characteristics were minimized. Recent studies of the auditory periphery suggest that the desired (spectral) pattern invariance with change in SPL is not met in the patterns of average firing rates on primary auditory neurons, but that level independence is more nearly preserved in the pattern of interspike intervals [Sachs and Young, J. Acoust. Soc. Am. 68, 858 (1980)]. However, interpretation of interspike interval data requires an autocorrelation-like analysis that is presumably performed more centrally. Thus peripheral frequency selectivity is only one of several factors constraining the input representation of speech sounds, and builders of speech processing systems are perhaps on safer grounds at this time if they rely on psychophysical data (e.g., critical-band concepts) to guide their designs. One promising new psychophysical task is a perceived phonetic distance paradigm. Use of this technique to design a perceptually motivated distance metric for phonetic recognition will be discussed. [Work supported in part by an NSF grant.]
Syllable type influences the acoustic consequences of variations in lexical stress
Authors: Summers Walter V. , Soil Sigfrid D.
Published: October 2005

Most words forming lexical stress pairs in English have a sonorant or fricative adjacent to one side of the syllable boundary and a stop consonant adjacent to the other side, or they have sonorants or fricatives on both sides. Very few have stops on both sides of the boundary. The acoustic manifestations of this apparent phonological constraint on lexical stress items were examined in multiple tokens of 12 lexical stress pairs produced by ten linguistically naive speakers. Differences in vowel formant frequencies, vowel duration, and fundamental frequency contours between stressed and unstressed syllables were measured. In general, greater vowel formant and duration changes were seen in syllables with sonorants or fricatives, while stop syllables were less influenced by variations in lexical stress. These contrasts suggest that syllables with sonorants or fricatives may occur frequently in lexical stress items because they more clearly convey information for stress contrasts. Implications for perceptual processing of lexical stress information are discussed.
Coupling of acoustic normal modes in shallow water
Authors: McDaniel Suzanne T.
Published: October 2005

In shallow water, coupling between acoustic normal modes may occur due to interaction with irregular boundaries. Two treatments of mode coupling are presented and discussed: a stochastic theory applicable to scattering due to ocean surface and bottom roughness, and a deterministic theory applicable to large-scale range dependent features. The advantages and limitations of each of these methods is discussed and results are compared with those obtained from alternative methods of treating the same phenomena. It is concluded that both the stochastic and deterministic mode-coupling models provide a powerful tool for increasing our understanding of the effect of boundary irregularities on shallow water acoustic propagation. [Work supported by NAVSEASYSCOM, NSEA-63R-1.]
Shallow-water propagation: The role of the branch-line integral in the Pedersen-Gordon model
Authors: Hall Marshall
Published: October 2005

Solutions to the wave equation for sound-speed profiles which are terminated by an isospeed half-space can be expressed as a sum of discrete modes plus a branch-line integral (BLI). The BLI is often insignificant, but can be of great significance in duct propagation at frequencies near the cutoff freqency of the duct. In one example [D. C. Stickler, J. Acoust. Soc. Am. 57, 856–-861 (1975)], the BLI dominated the mode contribution for ranges out to 30 km. The Pedersen-Gordon normal-mode model, on the other hand, terminates the profile with a “furry” half-space in which the sound speed approaches zero as z−1/2 as the depth (z) approaches infinity. The Pedersen-Gordon model is applied to Stickler's shallow-water duct, and the limit of the results for the sound field (based on only a mode sum), as the sound-speed gradient in the half-space (evaluated at its interface with the duct) approaches zero, is determined. This limit is found to be equal to Stickler's result for the sum of both the BLI and the mode contributions. The theoretical reasons for this equality are discussed.
Asymptotic results for the motion of finite fluid-loaded structures
Authors: Innes D. , Crighton D. G.
Published: October 2005

The response of a finite plane fluid-loaded structure under local excitation is governed by a generalized Wiener-Hopf functional equation whose solution has previously been found asymptotically for large plate size or light fluid loading (the general approach being nonetheless valuable in that it encompasses the full range of edge conditions and the absence or presence of a surrounding baffle). Here we use the smallness of a “fluid loading at coincidence” parameter ε to find asymptotic solutions for a strip membrane or plate, unbaffled and with free edges, under line force drive, and covering the whole range of normalized frequency Ω and strip width L. Resonant response is identified, both at moderate frequencies where fluid loading is light, and at low frequencies where it is heavy; the resonant response is calculated, both on the structure and in the fluid. Approximate methods, yielding results in precise agreement with those derived here, are devised for numerous areas of the (Ω, L) plane. [Work supported by ONR Code 421 and DTNSRDC Carderock Code 1900.]
Introduction to parameters defining surface roughness
Authors: Franz Gerald J.
Published: October 2005

Interest in surface roughness runs the gamut from terrestrial to the miscrosopic. Descriptions will be given of roughness in topography, ocean surfaces, optical and acoustical scattering, friction and wear, electrical and thermal contact, vehicle vibration and noise, and hydrodynamic and aerodynamic drag and noise. Regions of interest will be described in terms of spatial frequency and applications to vibration excitation and noise generation will be emphasized. Activities in standards and reference specimens, descriptive parameters, molding and replication, and instruments and instrument calibration will be described and areas in need of further research will be pointed out.
FFT analysis of surface roughness
Authors: Brock Michael
Published: October 2005

Many different parameters have been defined to give a description of a mechanical surface structure. Ra (the arithmetic mean value of the profile signal), Rq (the rms value), and Rmax (the maximum peak-to-peak value) are some of the most commonly used. Also, the surface profile, height distribution, and autocorrelation function are often shown. In many applications, however, neither the parameters nor the surface profile give sufficient information about the surface. Examples are even found where use of the “conventional” parameters gives misleading results. The need for a more advanced surface characterization covering a wide range of applications in one single parameter is obvious. Fourier analysis of the surface profile seems to be the best answer to this need, letting the wavelength spectrum be the parameter describing the surface. The above considerations will be further discussed. A series of typical mechanical surfaces has been tested, and their wavelength spectra will be shown and interpreted. The relation to the surface profile and the conventional parameters will be mentioned, and an example of use of the wavelength spectrum to compare different lubricants used in a shaving process will be given.
Time of spike initiation in the auditory nerve in relation to basilar membrane motion
Authors: Ruggero Mario A. , Rich Nola Cofer
Published: October 2005

Single-unit activity was recorded in the auditory nerves in chinchillas. Period histograms were constructed for responses to tones, 30–100 Hz, presented at near-threshold levels for 40 s. In neurons with characteristic frequencies (CFs) greater than 7 kHz, period histogram phases indicate that spikes are initiated synchronously with rarefaction at the eardrum. Therefore in light of cochlear microphonic data of Dallos [J. Acoust. Soc. Am. 48, 489–499 (1970)], we conclude that the excitation of basal neurons occurs in phase with basilar membrane displacement toward scala tympani. In neurons with CFs between 2 and 7 kHz, phases increasingly lag with decreasing CF, with a slope of about +100°/(octave CF). Such a slope is much steeper than predicted by basilar membrane mechanics. We therefore conclude that the extra phase lags are introduced by some spatially varying property of the organ of Corti, such as hair-cell stereociliar length. [Work supported by NIH.]
Nonmonotonic behavior of cat ABR amplitude at high intensities
Authors: Walsh E. J. , McGee J. , Javel E.
Published: October 2005

At low intensities (< 60 dB SPL), the amplitude of the auditory brain stem evoked response (ABR) is a linear function of signal intensity. Above 60–70 dB SPL response amplitudes decline, sometimes dramatically, and reach a minimum at 80–90 dB SPL. Above 80–90 Db SPL, ABR wave amplitudes increase rapidly. These features are represented in all ABR components with the effect being most pronounced in waves I and V. The nonmonotonic ABR amplitude behavior exists at high intensities (> 100 dB SPL) in kittens less than four postnatal weeks old, and is more pronounced in kittens less than three to four months of age than in adult animals. Also, nonmonotonic behavior disappears for some time following exposure to a high-intensity sound. Nonmonotonic growth of ABR amplitude is in many respects similar to that observed in responses of auditory nerve fibers. [Work supported by NINCDS grant NS-14880 and by a Biomedical Research Supplement Grant from NIH.]
Frequency specific effects of broadband noise on wave V or the brainstem-evoked response
Authors: Burkard Bob , Hecox Kurt
Published: October 2005

Brainstem-evoked responses were obtained to 1000 and 4000 Hz, 60-dBnHL tone bursts in the presence of continuous broadband noise ranging from a no-noise control to 10 dB S/N. In a second study, using 50-dBnHL clicks, narrow spectra responses were obtained by the subtractive masking technique of Don and Eggermont [J. Acoust. Soc. Am. 63, 1084–1092 (1978)]. In the subtractive masking paradigm, continuous noise was added at levels ranging from a no-noise condition to 10 dB S/N. Amplitude decrements across noise levels were comparable for both tone-burst frequencies. Wave V latency increased with increasing noise levels for both tone bursts; however, latency changes were greater for responses to the 1000-Hz tone bursts. In the derived-band paradigm, the higher frequency responses showed greater amplitude decreases and latency increases with increasing noise level. Possible reasons for these apparently paradoxical results are discussed. [Work supported by NIH.]
Predicting and measuring speech intelligibility in rooms
Authors: Houtgast T. , Steeneken H. J. M.
Published: October 2005

A well-known concept—the Modulation Transfer Function MTF—which has only recently been adapted to the field of room acoustics, can successfully be used for predicting or measuring speech intelligibility in rooms. The MTF in room acoustics characterizes the quality of sound transmission between two points in a room by specifying the reduction of the original fluctuations in the signal (more specifically, the reduction of the modulation depth as a function of modulation frequency), brought about by interfering noise and/or reverberation. The relevance of this approach for speech intelligibility has been verified by a large-scale international test: it was found that the results of the MTF analysis (in which an MTF is converted into a single index, the Speech Transmission Index STI) relate well with the mean results of various intelligibility tests for different languages. The accessibility of the MTF approach for architects and acousticians has been substantiated by (1) the development of a calculation scheme for predicting the STI from the design specifications of a room and (2) the development of specific equipment for measuring the STI in actual conditions.
Organ of Corti of the fetal mouse in culture
Authors: Sobkowicz Hanna M. , Rose Jerzy E.
Published: October 2005

The organ of Corti of the fetal mouse in culture provides a unique opportunity to study the development of the afferent innervation of the hair cells. Cultures were explanted between 13 to 18 days of gestation and maintained up to 14 days. The leading finding is that all the major fiber systems that are present in the intact animal develop also in culture. Formation of radial patterns in the spiral ganglion follows (1) the disappearance of the subepithelial plexus and a pronounced reduction in the total number of peripheral fibers, and (2) rearrangement of spiral ganglion cells into distinct groups that give rise to individual radial bundles. Development of the innervation of inner hair cells begins with an arrest of the growth of radial fibers around the inner hair cells, formation of neurofibrillar caps, and formation of the inner spiral plexus and bundle. Outer spiral fibers penetrate the outer hair cell region as the “deep radial fibers” of Tello. This is followed in succession by (a) a stationary period during which growth is suspended, (b) positioning of the growing tips toward the base, (c) a period of resumed growth in a spiral direction, and (d) rearrangement of fibers into three outer spiral bundles and formation of neurofibrillar caps upon the outer hair cells. Our findings show that orderly innervation patterns, indistinguishable from those observed in the intact animal, are produced in culture. Thus the development of innervation in the organ of Corti of the mouse appears to be determined by local factors. [Work supported by NSH grants NS15061, NS12732, and NS2P3-03352.]
Speech intelligibility in rooms
Authors: Latham Howard G.
Published: October 2005

This paper reviews developments in the science of speech intelligibility in rooms, and discusses the need for further work. Over the last 60 years, knowledge on this subject area of auditorium acoustics has been ascertained by observation and experiment, critically tested, systematized, and brought under a set of general principles. Objective indices are now available for measuring and predicting speech intelligibility in rooms without the need for traditional subjective testing procedures. Thus a more widespread application of intelligibility criteria in auditorium design is to be expected in future work. Parallel with the developments in objective and subjective measurement techniques, the computer prediction of reflection patterns in rooms has been developed so that speech intelligibility levels can now be ascertained during design, and acoustic faults remedied before construction commences. However, further work is needed to establish a valid basis for speech intelligibility design criteria based on objective measurements. To this end, a catalog of subjective and objective measures of speech intelligibility could be determined for a set of conditions in well-known auditoria. The result would be a relative scale of intelligibility values for use by practitioners. [Work supported by the SERC, United Kingdom.]
Listening devices in auditoriums for listeners with perceptual problems
Authors: Nábělek Anna K.
Published: October 2005

Acoustic criteria for auditoriums have been developed for listeners with normal perceptual skills. In consequence, these criteria applied to room acoustics may not be good enough for listeners with perceptual deficiencies. Perceptual problems are usually associated with congenital or acquired hearing losses, but also, elderly listeners who might have only slightly less acute hearing then their younger counterparts find listening in some auditoriums very difficult. Three parameters contribute to such problems: sound pressure level too low, speech-to-noise ratio too low, and reverberation too long. When acoustic conditions become unsatisfactory, many listeners cease attending lectures, art performances, etc. In some communities loss of elderly listeners might consist of a significant reduction in public support of drama theaters or concerts. The so-called “group amplification systems” or “listening devices” can provide help for listeners with perceptual problems. The main principle of such devices is to pick up the signal close to the source and deliver it directly to the listener's ears. In such a way the signal can be individually amplified and delivered without background noise and reverberation. The following systems which are presently in use will be discussed: (1) hard wired, (2) induction loop, (3) amplitude modulation, (4) frequency modulation, and (5) infrared. All these systems will be discussed for the use of listeners with and without hearing aids. [Work supported by NIH.]
Cross-language study of children's prosodic development—II: Syllabic duration, F0, and intensity in 2 year olds' words
Authors: Allen George D.
Published: October 2005

A previous paper [J. Acoust. Soc. Am. Suppl. 1 69, S82 (1981)] described a corpus of utterances produced by 2- through 5-year-old speakers of French, German, and Swedish. The 2 year olds in this study named pictures, whose names were chosen for their polysyllabic structure and comparable segmental composition between languages (e.g., crocodile, Krokodil, krokodil). The six children of each language group were tape recorded twice, six months apart. Spectrographic and oscillographic analyses of these children's picture-naming responses are presently under way, and data will be presented describing the absolute and relative durations, fundamental frequencies, and intensities of the syllables making up each word. Comparisons both within and between groups will be drawn, and evidence for prosodic development over the six month's interval between recordings will be discussed. [Research supported by the National Science Foundation.]
Comparison of VOT in 2-year-old French-, German-, and Swedish-speaking children
Authors: Allen George D.
Published: October 2005

A previous paper [J. Acoust. Soc. Am. Suppl. 1 69, S82 (1981)] described a corpus of utterances produced by 2- through 5-year-old speakers of French, German, and Swedish. The 2 year olds in this study named pictures, whose names were chosen for their comparable segmental structure between languages (e.g., balloon, Ballon, ballong). The six children of each language group were tape recorded twice, six months apart. Spectrographic and oscillographic analyses of these children's picture-naming responses are presently under way, from which VOT measurements will be obtained. Comparisons of these VOT data, both within and between groups, will be presented. Evidence for articulatory development over the six months' interval between recordings will be discussed. [Research supported by the National Science Foundation.]
Acoustic analyses of closant sounds in infants' comfort-state utterances
Authors: Bauer Harold R. , Kent Ray D.
Published: October 2005

Closants, or consonant-like sounds, were described acoustically using 16-kHz spectrograms and LPC or FFT analyses based on waveforms sampled at 20 or 40 kHz. The four major closant types were stops, fricatives and affricatives, vibrants or trills, and glides. Compared to similar sounds in adult speech, the closant sounds of the 3-, 6-, and 9-month-old infants had significant regions of energy in the higher frequencies, i.e., to and above 14 kHz. An infant's production of closants having the same manner and place often was highly variable in spectral and temporal features, even in the case of reduplicated babbling. For example, the occurrence of stop bursts sometimes was highly variable with respect to voice onset or offset. However, there were instances of reliable reproduction of a basic sound pattern or phonetic property. Acoustic features are described for various places of articulation of stops, fricatives, and trills. The discussion of the data emphasizes (1) the major dimensions of acoustic contrast that are used by infants in the first year of life, (2) implications of the spectral data for auditory and speech motor self-stimulation by normal-hearing and hearing-impaired infants, and (3) the continuity and discontinuity of early closant formation with later phonetic development in the preword and first-word stages. [Work supported by NIH.]
The timing of speech and hand motor coordination in language delayed children
Authors: Amorosa Hedwig
Published: October 2005

Parameters of speech and hand motor control were measured in 23 dysphasic children and 35 controls from 5–12 years of age. The timing parameters measured at the segmental level are the VOT for initial stop consonants, the length of vowels, and the duration of the p closure in the word “ipi.” The timing parameters at the suprasegmental level were the length of syllables in isolated words and in longer utterances. In addition the timing control of finger coordination was investigated with a tapping task. Timing parameters for speech and fine motor control of the hands are more variable in the dysphasics than in the controls. The results suggest that such high variability contributes to the impairment of intelligibility of speech in dysphasics. Since high variability in the tapping task was also obtained, one could conclude that a general impairment of timing is the basis for the deficit in these children. The value of neurological models of timing control and of biological clocks to explain the findings will be discussed.
Anchoring consonantal perturbation of fundamental frequency
Authors: Kingston John
Published: October 2005

The larynx is raised during voiceless obstruents, elevating fundamental frequency (F0) on the following vowel perceptibly above its Svalue after voiced obstruents or nasals. Though vertical larynx movement is not closely synchronized with vowel onset [C. J. Riordan, Report of the Phonology Laboratory, UC, Berkeley 5, 114–126 (1980)], it does not follow a uniform contour independent of consonant type either, but is loosely anchored to oral release. I measured F0 of vowels following glottal stop, voiced and voiceless (oral) stops, ejectives, and nasals produced by a Tigrinya speaker. Glottal stop, voiceless stops, and ejectives all elevated F0, but voiced stops and nasals did not. F0 fell 6–7 Hz during the first 50 ms after all elevating consonants and rose 2–3 Hz after nonelevators. Taking nasal values as a baseline, F0 at vowel onset was 16 Hz higher after glottal stop, 13 Hz higher after voiceless stops, but only 8 Hz higher after ejectives. F0 should be higher after ejectives than voiceless stops because the larynx is actively raised during ejectives to compress air in the oral cavity. However, voice onset time (VOT) for ejectives is 1.5 times that of oral stops, so the larnyx may have fallen back before voicing begins. The F0 contour after an ejective fits that following a voiceless stop if it is offset by the difference in their VOTs.
Effects of accent on vowel duration in Japanese
Authors: Beckman M. E.
Published: October 2005

It has been known for some time that accent (i.e., lexical stress) is a major factor affecting vowel duration in English. An experiment was conducted to see whether accent has a similar effect in Japanese. Vowel durations were measured in tokens of minimally contrasting two-syllable words uttered by several native speakers of standard (Tokyo) Japanese. The mean duration for accented vowels was only slightly longer than for unaccented vowels, and when lengths of V1 and V2 were plotted against each other, there was considerable overlap between the data point sets of pairs of contrasting words. It was concluded that accent has only a minimal effect on vowel duration in Japanese.
Speakers' ability to control vocal tract output: II. Intervocalic obstruent durations and VOT
Authors: Cariski Denise , Weismer Gary
Published: October 2005

In this paper we report data on speakers' attempts to control the duration of intervocalic stop and fricative durations, as well as voice-onset times (VOT). For these experiments, the utterances are of VCV form, with stress assigned to the CV segment. Prior to being told that they are to generate “controlled” durations for the segments identified above, subjects are asked to produce multiple repetitions of each test syllable so that stable estimates of central tendencies and dispersions are obtained. Then subjects are required to reproduce three different target durations for each of segments identified above; one of these target durations approximates a subjects' typical duration for a particular segment, whereas the remaining two targets are longer and shorter than the typical duration. Subjects are given on-line knowledge of results to determine how well information concerning a previous production can be used to modify the next attempt to match a target. Early results indicate that VOT is the most difficult “segment” to control. [Work supported by NIH Program Project NS 13274.]
Coherent sound scatter from a rough interface between fluids for arbitrary impedance contrasts and various roughness element shapes
Authors: Tolstoy I.
Published: October 2005

The theory of Biot scatter is generalized to cover the case of a rough interface between two fluids of arbitrary density (ρ) and sound velocity (c) contrasts, for roughness elements having spheroidal or cylindrical shapes. Critical in the derivation is the condition of imbededness which says that, in a system of coordinates moving with the fluid in the medium of incidence, a scattering (roughness) element does not move normally to the interface. This condition leads to a simple form for the boundary condition obeyed by the scattered field whilst ensuring that the backscatter from a hemispheroid on the surface of the fluid (ρ2, c2) and protruding into the half-space (ρ1, c1) is equivalent to that of a whole spheroid (ρ2, c2) in a full space (ρ1, c1. A number of numerical examples are examined and it is concluded that pebbles or nodules scattered evenly on the ocean bottom offer optimum conditions for observing the boundary roughness mode under field conditions: this is a true boundary wave which has so far been observed only in laboratory model work [Medwin et al., J. Acoust. Soc. Am. 66, 1131–1134 (1979)]. [This work was supported by ONR.]
Boundary wave generation by coherent multiple scatter at a randomly rough rigid surface
Authors: Jordan Edgar A. , Medwin Herman
Published: October 2005

In a series of papers starting in 1979 (J. Acoust. Soc. Am. 66, 1135–1144), I. Tolstoy has shown that the Biot boundary conditions for coherent scatter from a low roughness surface [J. Acoust. Soc. Am. 44, 1616–1622 (1968)] can be applied effectively to various deterministically rough interfaces such as hemispherical or ellipsoidal bosses between dissimilar fluids, or between a solid and a fluid. A boundary wave is predicted that is particularly strong at near grazing scatter provided that the low roughness criterion holds: ka < kh ⩽ 1, where a is the radius of the hemispherical bosses, h is the distance between them. Since it diverges cylindrically rather than spherically, the boundary wave can become stronger than a direct wave propagating over a smooth plane surface. Previously, this “Biot boundary wave” has been experimentally verified in the fluid over a rigid plane surface constructed of hemispherical scattering elements [H. Medwin et al., J. Acoust. Soc. Am. 66, 1131–1134 (1979)]. The Biot boundary wave has now been experimentally evaluated at grazing propagation over a randomly rough rigid surface of Gaussian rms height σ = 2.3 mm, Gaussian rms slope 1.15, and isotropic correlation length L = 4.8 mm. The empirically determined ratio of mean boundary wave amplitude 〈PB〉 to smooth surface direct volume wave amplitude PD at range R, valid to kL ⩽ 1, is 〈PB〉/PD = 0.27 σ k3/2(2πR)1/2. This result is essentially the same as that for a deterministic surface of hemispherical bosses when that is rewritten in terms of its rms height. For the randomly rough surface the correlation length replaces the separation between hemispheres in the “low roughness” criterion. [Work supported by Office of Naval Research.]
A modified smoothing method for rough surface scattering
Authors: Watson John G.
Published: October 2005

The statistics of the acoustic field scattered from a rough surface separating two fluids are obtained using a modified smoothing method. The modification employed yields enhanced accuracy for surfaces with large correlation lengths. [Work supported by ONR.]
Measurement of the coherent transfer function of a forward surface scatter channel using a parametric array
Authors: Singhal Sharad , Zornig John G.
Published: October 2005

The parametric array is able to project sidelobe-free, narrow beams of sound at low frequencies with small transducers, making it attractive for use in model tank surface scattering experiments. The sidelobe-free nature of the projected beam makes it possible to simply and precisely describe the insonified area on the surface. Using a parametric array, measurements of forward surface scattering coherence have been made at low grazing angles for various surface conditions. The results of these measurements are displayed and compared to earlier measurements made with simple projectors and to the predictions of current analytical models. [Work supported by NSF.]