This study investigated the effects of altered auditory feedback on stuttering frequency during speech production at two different speech rates, Nine stutterers, who exhibited at least 5% dysfluency during a reading task, served as subjects. They read eight different passages (each 300 syllables in length) while receiving four conditions of auditory feedback: nonaltered, masking, delayed, and frequency altered. For each auditory feedback condition, subjects read at both a normal and a fast rate. Results indicated that stuttering frequency was significantly decreased during conditions of delayed and frequency altered auditory feedback at both speech rates (p < 0.05). These findings refute the notion that a slowed speech rate is necessary for fluency enhancement under conditions of altered auditory feedback. Considering previous research and the results of this study, it is proposed that there may be two interdependent factors that are responsible for fluency enhancement: alteration of auditory feedback and modification of speech production.

Recent trends towards the intensification of urban development to increase urban densities and avoid sprawl should be accompanied by research into the potential for related health impacts from environmental exposure. The objective of the current study was to examine the effect of the built environment and land use on levels of environmental noise. Two different study areas were selected using a combination of small area census geography, land use information, air photography, and groundtruthing. The first study area represented residential land use and consisted of two-to three-story single-family homes. The second study area was characteristic of mixed-use urban planning with apartment buildings as well as commercial and institutional development. Study areas were subdivided into six grids, and a location was randomly selected within each grid for noise monitoring. Each location was sampled four times over a 24-h day, resulting in a total of 24 samples for each of the two areas. Results showed significant variability in noise within study areas and significantly higher levels of environmental noise in the mixed-use area. Both study areas exceeded recommended noise limits when evaluated against World Health Organization guidelines and yielded average noise events values in the moderate to serious annoyance range with the potential to obscure normal conversation and cause sleep disturbance.

No abstract

Double ultrasonic beams acoustooptical modulators require high pre cisiorl driviri electric signals for stabile control of frequency rati() arid phase shift, High precision digital synthesis niethod has been developed for the generation of high quality periodic signals. Maximum frequency range of a synthesized waveforms is determined by the speed of avii.1abie RAM (Random Access Memory) and an available P/A converter. A computer-based digital function generator can generate any arbitrary type of signal in the frequency range deterniiried by the speed of PAM and the ..P/A converter. Frequency stability is determined by quartz clock of the P/A converter and is in the order of I /1OPeriodic waveforms can be synthesized, stored and then played continuously by looping through the RAM huffer I HTRODUCT I ON A new, h I gh prec i s i on d i gi ta 1 syntlies i s method has been developed for the generition of high quality periodic signals and some aousto--opticai appi ication is suggested. Maximum frequency rare of a synthesized waveform is determined by the speed of available RAM (Random Access Memory) and in available D/A converter. With a n-bit P/A converter one can get. S/N :: 6*n [dB] (for exampi e, for 8-hit P/A,dli). With the proposed method, high quality sinusoidal, square, trangular, pulse, pseudo--ratidoiii noise and other types of wayes can he generated. Analog signal generators suffer from a lack of 0-8194-1 070-5/92/$4.Q0 SPIE Vol. 1844 Acousto-Optics and Applications (1992)1 251 Downloaded From: http://proceedings.spiedigitallibrary.org/ on 06/17/2016 Terms of Use: http://spiedigitallibrary.org/ss/TermsOfUse.aspx