Assessment of a numerical model to reproduce event-scale erosion and deposition distributions in a braided river.

Numerical morphological modeling of braided rivers, using a physics-based approach, is increasingly used as a technique to explore controls on river pattern and, from an applied perspective, to simulate the impact of channel modifications. This paper assesses a depth-averaged nonuniform sediment model (Delft3D) to predict the morphodynamics of a 2.5 km long reach of the braided Rees River, New Zealand, during a single high-flow event. Evaluation of model performance primarily focused upon using high-resolution Digital Elevation Models (DEMs) of Difference, derived from a fusion of terrestrial laser scanning and optical empirical bathymetric mapping, to compare observed and predicted patterns of erosion and deposition and reach-scale sediment budgets. For the calibrated model, this was supplemented with planform metrics (e.g., braiding intensity). Extensive sensitivity analysis of model functions and parameters was executed, including consideration of numerical scheme for bed load component calculations, hydraulics, bed composition, bed load transport and bed slope effects, bank erosion, and frequency of calculations. Total predicted volumes of erosion and deposition corresponded well to those observed. The difference between predicted and observed volumes of erosion was less than the factor of two that characterizes the accuracy of the Gaeuman et al. bed load transport formula. Grain size distributions were best represented using two φ intervals. For unsteady flows, results were sensitive to the morphological time scale factor. The approach of comparing observed and predicted morphological sediment budgets shows the value of using natural experiment data sets for model testing. Sensitivity results are transferable to guide Delft3D applications to other rivers.

Phonational profiles of male trained singers and nonsingers.

The purpose of this study was to compare the mean speaking fundamental frequency (SFF), speaking frequency range, and mean speaking intensity for a group of trained male singers and a group of age-matched non-singers in three age ranges: 20 to 35 years old; 40 to 55 years old; and older than 65 years. Each subject was recorded as he read "The Rainbow Passage" and produced the vowel /a/ to the limits of his phonational frequency range. The data indicated that the mean SFF of the nonsingers was significantly lower among the middle-aged speakers than with the young or elderly. In contrast, the tenors exhibited no age-related SFF trends, and the young bass/baritones exhibited lower SFF levels than the middle-aged or elderly. The elderly nonsingers produced frequency ranges that were smaller than any other group. Finally, the young nonsingers used greater speech intensity than did the other groups.

Cricoarytenoid arthritis and ankylosing spondylitis.

A variety of systemic diseases may manifest with laryngeal symptoms. Cricoarytenoid arthritis with or without limitation of vocal fold motion is an example. It has been described in up to 25% of rheumatoid patients. Ankylosing spondylitis is classified among the seronegative spondylarthritides. Besides its systemic features, rare reports of cricoarytenoid involvement have been published. Six previous cases reported have been characterized by a long history of ankylosing spondylitis before the cricoarytenoid joint involvement occurred. We describe only the seventh case of cricoarytenoid arthritis secondary to ankylosing spondylitis and the first patient (to our knowledge) to present with bilateral vocal fold fixation as the initial presenting symptom.

Phonational profiles of female professional singers and nonsingers.

Measures of the SFF, vocal intensity, phonational range, and habitual pitch level are reported for 39 professional singer and 39 nonsinger females, who were divided into three age groups (young, middle, and old age), with the professionals further divided into sopranos and altos. Each read the "Rainbow Passage" and spoke extemporaneously, from which measures of the SFF and vocal intensity were calculated; phonational range and habitual pitch levels were also determined. No significant differences were noted between the reading and speaking tasks. The SFF and intensity levels were significantly higher for the professionals in comparison to the nonsingers, but only for certain age groups. Moreover, whereas the nonsinger SFF levels varied significantly as a function of age, those for the professional singers did not. Although trends occurred, no significant differences were found for the mean phonational range or habitual pitch levels when the professionals and nonsingers were compared.

Electroglottography and vocal fold physiology.

The electroglottogram (EGG) is known to be related to vocal fold motion. A major hypothesis undergoing examination in several research centers is that the EGG is related to the area of contact of the vocal folds. This hypothesis is difficult to substantiate with direct measurements using human subjects. However, other supporting evidence can be offered. For this study we made measurements from synchronized ultra high-speed laryngeal films and from EGG waveforms collected from subjects with normal larynges and patients with vocal disorders. We compare certain features of the EGG waveform to (a) the instant of the opening of the glottis, (b) the instant of the closing of the glottis, and (c) the instant of the maximum opening of the glottis. In addition, we compare both the open quotient and the relative average perturbation measured from the glottal area to that estimated from the EGG. All of these comparisons indicate that vocal fold vibratory characteristics are reflected by features of the EGG waveform. This makes the EGG useful for speech analysis and synthesis as well as for modeling laryngeal behavior. The limitations of the EGG are discussed.

Acoustic correlates of vocal quality.

We have investigated the relationship between various voice qualities and several acoustic measures made from the vowel /i/ phonated by subjects with normal voices and patients with vocal disorders. Among the patients (pathological voices), five qualities were investigated: overall severity, hoarseness, breathiness, roughness, and vocal fry. Six acoustic measures were examined. With one exception, all measures were extracted from the residue signal obtained by inverse filtering the speech signal using the linear predictive coding (LPC) technique. A formal listening test was implemented to rate each pathological voice for each vocal quality. A formal listening test also rated overall excellence of the normal voices. A scale of 1-7 was used. Multiple linear regression analysis between the results of the listening test and the various acoustic measures was used with the prediction sums of squares (PRESS) as the selection criteria. Useful prediction equations of order two or less were obtained relating certain acoustic measures and the ratings of pathological voices for each of the five qualities. The two most useful parameters for predicting vocal quality were the Pitch Amplitude (PA) and the Harmonics-to-Noise Ratio (HNR). No acoustic measure could rank the normal voices.

A model for vocal fold vibratory motion, contact area, and the electroglottogram.

The electroglottogram (EGG) has been conjectured to be related to the area of contact between the vocal folds. This hypothesis has been substantiated only partially via direct and indirect observations. In this paper, a simple model of vocal fold vibratory motion is used to estimate the vocal fold contact area as a function of time. This model employs a limited number of vocal fold vibratory features extracted from ultra high-speed laryngeal films. These characteristics include the opening and closing vocal fold angles and the lag (phase difference) between the upper and lower vocal fold margins. The electroglottogram is simulated using the contact area, and the EGG waveforms are compared to measured EGGs for normal male voices producing both modal and pulse register tones. The model also predicts EGG waveforms for vocal fold vibration associated with a nodule or polyp.

A comparison of stutterers and nonstutterers in a task of controlled voice onset.

The purpose of this study was to determine if stutters and nonstutters differed in their ability to initiate phonation repeatedly with a gentle voice onset. Ten stutterers and ten nonstutterers were asked to phonate the vowel /a/ with an average rise time slower than 52.3 dB/sec while starting the voice at or below 63 dB SPL. Voice productions were monitored by a voice monitor, which is used in the administration of the Precision Fluency Shaping Program. Measurements of number of attempts and time to reach criterion, percentage of correct productions, and intensity levels of each production were made. There were no significant differences between the two groups for any of the variables examined. Results were compared with other studies demonstrating phonatory differences between stutterers and nonstutterers.