Digital Audio Tape Research Articles

Does intonation have primitive units?

This study investigated whether listeners can interpret intonation based on partial rather than global fundamental frequency (F0) or pitch information. Matched Statements and echo questions were recorded digitally at 22 kHz sampling rate using a Computerized Speech Lab (CSL). Each production was stored on the CSL and edited by slicing the wave form into two parts that corresponded to terminal (last 150–200 ms span of the F0 contour) and preterminal (section of contour preceding the terminal region) F0 contour regions. A total of 92 stimuli was thus generated and recorded on a DAT tape. The tape was played to 96 young (20–28 years) and old (42–79 years) adults to determine if each stimulus was part of a statement or a question. For preterminal (PTL) stimuli, both groups successfully identified statements 91% and 88% of the time, respectively, compared to 72% each for questions. The respective scores for the terminal (TL) stimuli were 94% and 91% (statements) versus 91% and 87% (questions). Across groups, statements were easier to identify with both TL (p=0.002) and PTL (p=0.001) cues compared to questions. These findings suggest that intonation decoding might involve units smaller than global F0 contour. [Work supported by NIH (NIDCD) grant 5R03DC04955-02.]

Noise dosimeter for monitoring exposure to impulse noise

Commercially available noise dosimeters do not perform properly in impulsive noise environments because they suffer from instrumentation limitations and lack metrics that characterize impulse noise. In this paper, a design concept is proposed for an impulse noise monitoring dosimeter that addresses the current dosimeter’s limited capabilities and describes the various parameters that can appropriately be used to measure and evaluate exposure to impulse noise. The design concept is based on the accurate acquisition and storage of the original impulse waveform. For data analysis (using MATLAB) and calculation of “impulse noise metrics,” National Institute for Occupational Safety and Health (NIOSH) used a prototype impulse noise dosimeter system that consisted of a Bruel&Kjaer 4136 microphone and a Panasonic Digital Audio Tape Recorder. The proposed instrument would enable collection of data for validation of presently defined and yet to be defined metrics quantifying noise-induced permanent threshold shifts (NIPTS) resulting from impulse/impact exposures. It will also enable occupational safety and health professionals to make accurate measurements of ultimately approved metrics.

Curcumin Stimulates Cystic Fibrosis Transmembrane Conductance Regulator Cl– Channel Activity

Compounds that enhance either the function or biosynthetic processing of the cystic fibrosis transmembrane conductance regulator (CFTR) Cl(-) channel may be of value in developing new treatments for cystic fibrosis (CF). Previous studies suggested that the herbal extract curcumin might affect the processing of a common CF mutant, CFTR-DeltaF508. Here, we tested the hypothesis that curcumin influences channel function. Curcumin increased CFTR channel activity in excised, inside-out membrane patches by reducing channel closed time and prolonging the time channels remained open. Stimulation was dose-dependent, reversible, and greater than that observed with genistein, another compound that stimulates CFTR. Curcumin-dependent stimulation required phosphorylated channels and the presence of ATP. We found that curcumin increased the activity of both wild-type and DeltaF508 channels. Adding curcumin also increased Cl(-) transport in differentiated non-CF airway epithelia but not in CF epithelia. These results suggest that curcumin may directly stimulate CFTR Cl(-) channels.

Major Ongoing Stroke Trials

Major Ongoing Stroke Trials

非同期サンプリングデータに対する同期加算処理

The progress of digital audio technology has enabled the familiar use of products such as CD and DAT in acoustic measurement. For example, a signal reproduced with a CD player is inputted into a subject for measurement and a DAT recorder records its response. However, the sampling cannot be synchronized completely with the input signal, although both nominal sample rates are set up equally, because the player and recorder work independently. The most popular solution is to use software to perform the synchronous addition after converting the recorded signal into the original sampling rate. However, the rate conversion also has an error due to the windowing in the high-frequency region of the processed signal. This paper proposes a new method for averaging asynchronous sampling data to solve these problems. To evaluate performance, the transfer function of only measuring equipment estimated from asynchronous sampling data was compared with the measurement results in synchronous sampling conditions. Both results agreed within 0.1 dB, so the effectiveness of the new method was confirmed. In measuring the frequency response of a BPF when white noise is introduced, the proposed method was compared with the method using rate conversion. As a result, the noise reduction was almost the same, and the processing time was reduced to about one-fourth. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 161(2): 33– 41, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20455

Microembolic Signal Predicts Recurrent Cerebral Ischemic Events in Acute Stroke Patients With Middle Cerebral Artery Stenosis

Cerebral embolism is a common cause of stroke. Microembolic signals (MES) detected by transcranial Doppler represent ongoing embolisms, but the lack of reliable data about its clinical relevance hinders its widespread use in clinical practice. We prospectively monitored 114 consecutive acute ischemic stroke patients with middle cerebral artery (MCA) stenosis for MES. The signals on digital audio tape were analyzed by an independent observer who was blinded to all other data. All patients were followed-up for the occurrence of recurrent stroke or transient ischemic attack (TIA) in the indexed MCA territory. MES was detected in 25 (22%) patients. The mean number of MES was 18 (range, 1 to 102). MES were more common in patients with severe stenosis (10/21, 48%) than in those with mild-moderate stenosis (4/26, 15%) (Pearson chi2 P=0.02). During follow-up for a mean of 13.6 months (range, 1 to 32), 12 (12%) patients had further ischemic events (10 strokes and 2 TIAs) in the affected MCA region during follow-up. Among these, 7 (58%) had recurred within 1 month (1 recurred within 1 week, the other 6 patients had recurrences in week 3 or 4 after discharge), 3 within 6 months, 1 within 6 to 12 months, and the remaining 1 recurred after 1 year. The presence of MES was the only predictor of a further ischemic stroke/TIA by Cox regression (adjusted odds ratio, 8.45; 95% CI, 1.69 to 42.22; P=0.01) even after controlling for age, sex, diabetes, hypertension, previous stroke, smoking, and acute treatment. In acute stroke patients with MCA stenosis, MES predicts further cerebral ischemia. This procedure should be considered as part of routine investigation and might identify a group of patients who are most likely to benefit from antithrombotic treatment.

Nonword Repetition by Children With Cochlear Implants

Seventy-six children with cochlear implants completed a nonword repetition task. The children were presented with 20 nonword auditory patterns over a loud-speaker and were asked to repeat them aloud to the experimenter. The children's responses were recorded on digital audiotape and then played back to normal-hearing adult listeners to obtain accuracy ratings on a 7-point scale. The children's nonword repetition performance, as measured by these perceptual accuracy ratings, could be predicted in large part by their performance on independently collected measures of speech perception, verbal rehearsal speed, and speech production. The strongest contributing variable was speaking rate, which is widely argued to reflect verbal rehearsal speed in phonological working memory. Children who had become deaf at older ages received higher perceptual ratings. Children whose early linguistic experience and educational environments emphasized oral communication methods received higher perceptual ratings than children enrolled in total communication programs. The present findings suggest that individual differences in performance on nonword repetition are strongly related to variability observed in the component processes involved in language imitation tasks, including measures of speech perception, speech production, and especially verbal rehearsal speed in phonological working memory. In addition, onset of deafness at a later age and an educational environment emphasizing oral communication may be beneficial to the children's ability to develop the robust phonological processing skills necessary to accurately repeat novel, nonword sound patterns.

Source spectra for excised and latex phonatory models

An excised larynx model and a latex physical model were used to study acoustic spectra of the phonatory source as a function of subglottal pressure, glottal adduction, and vocal-fold length. A supraglottal vocal tract was not used, indicating that the acoustic signal corresponded to the output glottal flow. Each model was mounted over an -inch tracheal tube through which flowed pressurized, heated, and humidified air. The subglottal pressure and EGG signal (excised model) were recorded on a personal computer. The mean flow rate, mean subglottal pressure, and SPL were recorded manually, and adduction was specified by the use of interarytenoid shims. The output audio signals from the larynx models were recorded on a DAT recorder. Spectral information of the audio signal was obtained via FFT analysis (Matlab). Preliminary data indicate that the spectral slope did not have a constant dB/octave rate, and spectral slope had a primary dependence on subglottal pressure and a secondary dependence on adduction. Other acoustic details and the differences between the two models will be discussed. [Work supported by NIDCD Grant Number DC03566.]

Limitations of Using Dosimeters in Impulse Noise Environments

The National Institute for Occupational Safety and Health (NIOSH) investigated the capabilities of noise dosimeters to measure personal exposure to impulse noise. The two leading types of commercially available dosimeters were evaluated in terms of their ability to measure and integrate impulses generated from gunfire during live-fire exercises at a law enforcement indoor firing range. Sound measurements were conducted throughout the firing range using dosimeters, sound level meters, and a measurement configuration that consisted of a quarter-inch microphone and a digital audiotape recorder to capture the impulse waveforms. Personal dosimetry was conducted on eight shooters, an observer, and the range master. Peak levels from gunfire reached 163 decibels (dB), exceeding the nominal input limit of the dosimeters. The dosimeters “clipped” the impulses by acting as if the gunfire had a maximum level of 146 dB. In other cases, however, peak levels (e.g., 108 dB) were below the dosimeter input limits, but the dosimeters still showed a peak level of 146 dB. Although NIOSH recommends that sound levels from 80 to 140 dB (A-weighted) be integrated in the calculation of dose and the time-weighted average, our present data suggest this criterion may be inadequate. These results showed that some instruments are incapable of providing accurate measures of impulse sounds because of their electroacoustic limitations.

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Listening to a town: The urban soundscape as an image of the city

City dwellers often have a visual representation of their town. They are able to identify some areas from pictures. But, urban sounds are also a characteristic part of the city’s identity. A previous paper [C. Semidor, Proceedings 20th PLEA, Santiago, Chile (2003)] shows the possibility to distinguish the soundscape of a ‘‘car-free’’ Sunday from the soundscape of a Sunday with cars. The proposed method based on the so-called soundwalk could be very illustrative for this suggestion. These soundwalks are sound recordings made with a ‘‘dummy’’ head and a DAT recorder, on walks following a trajectory with different urban forms and, in this case study, in different towns where a tramway is running. The acoustical images (time versus frequency graphs) of the sound signals could be a representation of these soundscapes. This type of information could help urban planners and other town designers to improve the acoustic comfort of the cities. The objective of this approach is to valorize what is pleasant and agreeable in the urban sound environment.

Piling in fine and medium sand—a case study of ground and pile vibration

The paper presents the results of the measurement of ground and pile vibrations from a field investigation of prototype piling in which a steel casing of 600 mm diameter was driven in fine and medium sand for a depth of 16.4 m by impacting a hammer of mass 4100 kg dropped from a height of 2.4 m by a motorised winch fitted in a pile rig. In the case of ground vibration, both horizontal and vertical accelerations at 3 m, and vertical velocity at 15 m on the ground surface from the driven pile were measured. So also, vibration of the top of the already installed pile at 6.25 m from the driven pile was measured. Vibrations were measured using piezoelectric accelerometers and recorded using a 16-channel RT 145D DAT recorder. The recorded data were processed and acquired using DASYLAB data acquisition system. Time history plots of velocity and acceleration of ground were obtained. The maximum peak ground vertical velocity measured at a distance of 25 times the diameter of pile from the driven pile was 126.2 mm/s. The maximum vertical acceleration of the already installed pile situated at a distance of 10.42 times diameter of pile was 123.42 m/s 2 indicating the resonance of pile due to shock wave propagating in the soil medium. The time history of the ground vibration indicates its impulsive dynamic nature of short duration in contrast to the random periodic nature of ground waves generated by earthquake. Spectral analysis of the time histories of ground accelerations shows a dominant vertical frequency of 35.21 Hz and horizontal 25 Hz. The vertical frequency of pile was observed to be 25 Hz. Based on these spectral frequencies and going by the permissible vibration limits prescribed in various standards and codes, it has been found that the ground and pile vibrations were quite severe. Such severe ground vibration has got the potential of inflicting damage to structures in the vicinity. The problem can be quite serious in the midst of cluster of buildings in the urban habitat in the vicinity of pile driving.

Voice Onset Time production in older Caucasian- and African-Americans

In an earlier study (Ryalls, Zipprer and Baldauff, 1997) significant differences in Voice Onset Time (VOT) production were found between younger males and younger females, as well as between African-American and Caucasian-American speakers. In this study we attempted to replicate these significant effects for gender and ethnic background in a group of older speakers. Participants in this study were healthy normal speakers between 50 and 70 years of age and included 10 African-Americans and 10 Caucasian-Americans with 10 males and 10 females. Speakers in this study produced real words with each of the 6 stop consonants of English (/p/, /t/, /k/; /b/, /d/, /g/) combined with the three extreme vowels (/i/, /a/, /u/) in monosyllabic words ending with a voiceless stop. Each of these 18 stimuli were then read at least five times in random order within a repetition and recorded onto Digital Audio Tape (DAT). The Brown University Laboratory Interactive Speech System (BLISS, Mertus, 1999) was used to display wavef...

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Major Ongoing Stroke Trials

Comparison of 3 bonded lingual appliances by auditive analysis and subjective assessment

The aim of this prospective study was to compare for the first time the influences of lingual appliances of different dimensions on sound performance and oral comfort. The study group comprised 12 subjects (10 women, 2 men; mean age, 33.96 years). Their sound production was recorded by means of a digital audio tape recorder before, 10 minutes after, and 24 hours after placement of the different appliances for semiobjective assessment by 3 blinded speech professionals. This was followed by supplementary subjective ratings of sound performance and oral comfort by the patients. All lingual appliances induced significant impairment in sound performance and oral comfort. However, they varied significantly with respect to the degree of impairment. The smaller the appliance, the less pronounced the impairments it induced. The smallest changes were induced by a bonded canine-to-canine retainer, followed by customized lingual brackets and prefabricated lingual brackets. By using lower-profile customized brackets, the orthodontist can significantly enhance patient comfort and significantly reduce impairments of sound performance in comparison with prefabricated brackets with larger dimensions. Before placing a lingual appliance, however, patients should be briefed on possible effects such as impaired sound production and decreased oral comfort.

Observation of very low frequency emissions at Indian Antarctic station, Maitri

Recently, we have succeeded in recording VLF emissions at the Indian Antarctic station, Maitri (geom. lat. 62°S, geom. long. 57.23°E,L = 45) using a T-type antenna, pre/main amplifiers and digital audio tape recorder. VLF hiss in the frequency ranges 11–13 kHz and 13–14.5 kHz and some riser-type emissions in the frequency range 3–5 kHz and magnetospheric lines at about 6.2, 8.0 and 9.2 kHz are reported for the first time. The generation and propagation mechanism of these emissions are discussed briefly.

Changes in Teachers’ Voice Quality during a Working Day with and without Electric Sound Amplification

The present study investigated changes in the voice quality of teachers during a working day (a) in ordinary conditions and (b) when using electrical sound amplification while teaching. Classroom speech of 5 teachers was recorded with a portable DAT recorder and a head-mounted microphone during the first and the last lesson of a hard working day first in ordinary conditions and the following week using amplification. Long-term average spectrum and sound pressure level (SPL) analyses were made. The subjects’ comments were gathered by questionnaire. Voice quality was evaluated by 2 speech trainers. With amplification, SPL was lower and the spectrum more tilted. Voice quality was evaluated to be better. The subjects reported less fatigue in the vocal mechanism. Spectral tilt decreased and SPL increased during the day. There was a tendency for perceived asthenia to decrease. No significant changes were observed in ordinary conditions. The acoustic changes seem to reflect a positive adaptation to vocal loading. Their absence may be a sign of vocal fatigue.

Noise Exposure Assessment and Abatement Strategies at an Indoor Firing Range

Exposure to hazardous impulse noise is common during the firing of weapons at indoor firing ranges. The aims of this study were to characterize the impulse noise environment at a law enforcement firing range; document the insufficiencies found at the range from a health and safety standpoint; and provide noise abatement recommendations to reduce the overall health hazard to the auditory system. Ten shooters conducted a typical live-fire exercise using three different weapons--the Beretta.40 caliber pistol, the Remington.308 caliber shotgun, and the M4.223 caliber assault rifle. Measurements were obtained at 12 different positions throughout the firing range and adjacent areas using dosimeters and sound level meters. Personal and area measurements were recorded to a digital audio tape (DAT) recorder for further spectral analysis. Peak pressure levels inside the firing range reached 163 decibels (dB) in peak pressure. Equivalent sound levels (Leq) ranged from 78 decibels, A-weighted (dBA), in office area adjacent to the range to 122 dBA inside the range. Noise reductions from wall structures ranged from 29-44 dB. Noise abatement strategies ranged from simple noise control measures (such as sealing construction joints and leaks) to elaborate design modifications to eliminate structural-borne sounds using acoustical treatments. Further studies are needed to better characterize the effects of firing weapons in enclosed spaces on hearing and health in general.

Maturation and Release of Interleukin-1β by Lipopolysaccharide-primed Mouse Schwann Cells Require the Stimulation of P2X7 Receptors

The P2X7 receptor, mainly expressed by immune cells, is a ionotropic receptor activated by high concentration of extracellular ATP. It is involved in several processes relevant to immunomodulation and inflammation. Among these processes, the production of extracellular interleukin-1beta (IL-1beta), a pro-inflammatory cytokine, plays a major role in the activation of the cytokine network. We have investigated the role of P2X7 receptor and of an associated calcium-activated potassium conductance (BK channels) in IL-1beta maturation and releasing processes by Schwann cells. Lipopolysaccharide-primed Schwann cells synthesized large amounts of pro-IL-1beta but did not release detectable amounts of pro or mature IL-1beta. ATP on its own had no effect on the synthesis of pro-IL-1beta, but a co-treatment with lipopolysaccharide and ATP led to the maturation and the release of IL-1beta by Schwann cells. Both mechanisms were blocked by oxidized ATP. IL-1beta-converting enzyme (ICE), the caspase responsible for the maturation of pro-IL-1beta in IL-1beta, was activated by P2X7 receptor stimulation. The specific inhibition of ICE by the caspase inhibitor Ac-Tyr-Val-Ala-Asp-aldehyde blocked the maturation of IL-1beta. In searching for a link between the P2X7 receptor and the activation of ICE, we found that enhancing potassium efflux from Schwann cells upregulated the production of IL-1beta, while strongly reducing potassium efflux led to opposite effects. Blocking BK channels actually modulated IL-1beta release. Taken together, these results show that P2X7 receptor stimulation and associated BK channels, through the activation of ICE, leads to the maturation and the release of IL-1beta by immune-challenged Schwann cells.

Songlike vocalizations from the Sumatran Rhinoceros (Dicerorhinus sumatrensis)

There are only 200 to 300 Sumatran rhinos (Dicermoceros sumatrensis) left in the world. Sumatran rhinos are solitary, and their native habitat is dense tropical forest and mountain moss forest. Three Sumatran rhinos, housed at the Cincinnati Zoo, were recorded using Statham Radio microphones and Sony TCD-D8 DAT recorders. Sumatran rhinos produce sounds described as eeps, 70 Hz–4 kHz (57–92 dB); whales, 100 Hz–3.2 kHz (87 dB); and whistle-blows, 17 Hz–8 kHz (100 dB). The whistle-blows contain high level infrasound that would be advantageous for use in the rhino’s forest habitat. Some Sumatran rhino vocalizations resemble humpback whale signals.