Thermoregulatory, Metabolic, and Cardiovascular Responses of Pregnant Women to Immersion and Immersion Exercise

Twelve healthy women underwent 20 minute periods of immersion rest (THao = 30° C) and immersion exercise (60¾ predicted VOa max) during weeks 15, 25, and 35 of gestation and 8 weeks postpartum. Maternal core temp, heat storage, immersion tissue insulation, and exercise tissue conductance were maintained across trials. temps were 1.1°C lower during pregnancy to prevent heat losses during immersion and heat gains during exercise. Oxygen uptake, heart rate, and systolic Skin blood pressure did not change with gestational timing during nonweight-bearing immersion exercise. The hydrostatic pressure of the water enabled exercise heart rates to be 17 bts/min lower than the predicted max land trials at the same energy expenditure. The heat dissipating and weight-supporting capacities of the water environment provided safe thermal, metabolic, and cardiovascular responses in pregnant women during aerobic exercise

Intelligibility prediction for speech mixed with white Gaussian noise at low signal-to-noise ratios

The effect of additive white Gaussian noise and high-pass filtering on speech intelligibility at signal-to-noise ratios (SNRs) from -26 to 0 dB was evaluated using British English talkers and normal hearing listeners. SNRs below -10 dB were considered as they are relevant to speech security applications. Eight objective metrics were assessed: Short-Time Objective Intelligibility (STOI), a proposed variant termed STOI+, Extended Short-Time Objective Intelligibility (ESTOI), Normalised Covariance Metric (NCM), Normalised Sub-band Envelope Correlation metric (NSEC), two metrics derived from the Coherence Speech Intelligibility Index (CSII), and an envelope-based regression method Speech Transmission Index (STI). For speech and noise mixtures associated with intelligibility scores ranging from 0% to 98%, STOI+ performed at least as well as other metrics, and under some conditions better than STOI, ESTOI, STI, NSEC, CSIIMid and CSIIHigh. Both STOI+ and NCM were associated with relatively low prediction error and bias for intelligibility prediction at SNRs from -26 to 0 dB. STI performed least well in terms of correlation with intelligibility scores, prediction error, bias and reliability. Logistic regression modelling demonstrated that high-pass filtering, which increases the proportion of high to low frequency energy, was detrimental to intelligibility for SNRs between -5 and -17 dB inclusive

On-axis sound pressure levels and sound power of normal speech for speech intelligibility, privacy and security

In room acoustics, assessment of speech intelligibility, privacy and security requires the on-axis sound pressure level and sound power level of speech at a normal vocal effort level. For open-plan offices, ISO 3382-3 quotes octave band sound pressure and sound power from 125Hz to 8kHz for unisex speech (an average of male and female speech) to represent speaking with a normal vocal effort. However, limited sound power data are available with phonetically balanced speech in one-third octave bands, particularly for male and female talkers below 160Hz where unisex speech may not be suitable. This paper reports anechoic measurements of normal speech (720 sentences) from 12 native British English speakers (six male, six female) in one-third octave bands from 63Hz to 20kHz thereby including the Extended High Frequency (EHF) range above 7kHz. Whilst male and female talkers are similar in the mid-frequency range, there is greater variation between individual talkers and between sentences in the low- and high-frequency ranges. Measured data are converted to octave bands for comparison with ISO 3382-3, ANSI S3.5 and EN 60268-16 to indicate which values may need reconsideration in the building acoustics frequency range

ARU speech corpus (University of Liverpool)

This corpus comprises single channel recordings of IEEE (Harvard) sentences (IEEE, 1969) spoken by twelve adult native British English speakers in anechoic conditions. IEEE (1969). Recommended practice for speech quality measurements, IEEE Transactions on Audio and Electroacoustics, 17 (3), 227-246. Principal |nvestigator: Professor Carl Hopkin

Silence and Voicing Accumulations in Italian Primary School Teachers With and Without Voice Disorders

Summary: Objectives. The relationship between the silence and voicing accumulations of primary school teachers and the teachers' clinical status was examined to determine whether more voicing accumulations and fewer silence accumulations were measured for the vocally unhealthy subjects than for the healthy subjects, which would imply more vocal loading and fewer short-term recovery moments. Methods. Twenty-six Italian primary school teachers were allocated by clinicians to three groups: (1) with organic voice disorders, (2) with subjectively mild organic alteration or functional voice symptoms, and (3) normal voice quality and physiology. Continuous silence and voicing periods were measured with the APM3200 during the teachers' 4-hour workdays. The accumulations were grouped into seven time intervals, ranging from 0.03-0.9 to 3.16-10 seconds, according to Italian prosody. The effects of group on silence and voicing accumulations were evaluated. Results. Regarding silence accumulations, Group 1 accumulated higher values in intervals between 0.1 and 3.15 seconds than other groups, whereas Groups 2 and 3 did not differ from each other. Voicing accumulations between 0.17 and 3.15 seconds were higher for subjects with a structural disorder. A higher time dose was accumulated by these subjects (40.6%) than other subjects (Group 2, 31.9%; Group 3, 32.3%). Conclusions. Although previous research has suggested that a rest period of a few seconds may produce some vocal fatigue recovery, these results indicate that periods shorter than 3.16 seconds may not have an observable effect on recovery. The results provide insight into how vocal fatigue and vocal recovery may relate to voice disorders in occupational voice users

Effect of Training and Level of External Auditory Feedback on the Singing Voice: Pitch Inaccuracy.

BackgroundOne of the most important aspects of singing is the control of fundamental frequency.ObjectivesThe effects on pitch inaccuracy, defined as the distance in cents in equally tempered tuning between the reference note and the sung note, of the following conditions were evaluated: (1) level of external feedback, (2) tempo (slow or fast), (3) articulation (legato or staccato), (4) tessitura (low, medium, or high), and (5) semi-phrase direction (ascending or descending).MethodsThe subjects were 10 nonprofessional singers and 10 classically trained professional or semi-professional singers (10 men and 10 women). Subjects sang one octave and a fifth arpeggi with three different levels of external auditory feedback, two tempi, and two articulations (legato or staccato).ResultsIt was observed that inaccuracy was greatest in the descending semi-phrase arpeggi produced at a fast tempo and with a staccato articulation, especially for nonprofessional singers. The magnitude of inaccuracy was also relatively large in the high tessitura relative to the low and the medium tessitura for such singers. Contrary to predictions, when external auditory feedback was strongly attenuated by the hearing protectors, nonprofessional singers showed greater pitch accuracy than in the other external feedback conditions. This finding indicates the importance of internal auditory feedback in pitch control.ConclusionsWith an increase in training, the singer's pitch inaccuracy decreases

A set of equations for numerically calculating the interaural level difference in the horizontal plane

The variation of interaural level difference (ILD) with direction and frequency is particularly complex and convoluted. The purpose of this work was to determine a set of parametric equations that can be used to calculate ILDs continuously at any value of frequency and azimuth in the horizontal plane. They were derived by fitting equations to ILDs derived from the azimuthal-dependence data tabulated by Shaw and Vaillancourt [(1985). J. Acoust. Soc Am. 78, 1120–1123] and assuming left-right symmetry. The equations are shown to fit those data to an overall RMS error less than 0.5 dB