Dimensions of the acoustic reflex as measured in a background of noise

This study examines whether background noise, presented at 10 dB below its reflex threshold, affects the acoustic reflex (AR) response for pure tones presented subsequent to the onset of the noise.

The acoustic approach to speech correction

This paper reviews a study to determine if an auditory approach to speech correction can be of beneift to hearing impaired children who have become visually oriented.

Comparison of three speakers along critical acoustic dimensions

This paper discusses a study done on the speech production of elementary school aged children.

Acoustic reflex measurements in normals and Meniere's Syndrome using pulsed stimuli

This paper reviews a study to determine the maximum rate the acoustic reflex can follow pulsed stimuli in normal hearing subjects and in subjects with Meniere's Syndrome.

Reception of acoustic speech signals as a function of sensation levels by hearing-impaired children

This paper is a review of a study to determine the sensation level at which the best discrimination and recognition occurs for severely and profoundly deaf children and the effect of distortion (peak clipping) has on the child's ability to recognize speech.

Perceptual validation of an acoustic metric for measuring vowel production by deaf children

This paper discusses a study to validate the metric developed in the Geers and Moog Cochlear Implant Study at CID to measure the speech production of hearing impaired children.

Classroom acoustics: the national acoustic standard

This paper discusses the variables affecting classroom acoustics and a case study examination of some local classrooms. Classrooms were measured against proposed American National Standards Institute (ANSI) standards and treatment options for improving acoustics are suggested.

The Influence of Body Condition on the Stopover Ecology of Least Sandpipers in the Lower Mississippi Alluvial Valley during Fall Migration

Many shorebirds are long-distance migrants and depend on the energy gained at stopover sites to complete migration. Competing hypotheses have described strategies used by migrating birds; the energy-selection hypothesis predicts that shorebirds attempt to maximize energy gained at stopover sites, whereas the time-selection hypothesis predicts that shorebirds attempt to minimize time spent at stopover sites. The energy- and time-selection hypotheses both predict that birds in better condition will depart sites sooner. However, numerous studies of stopover duration have found little support for this prediction, leading to the suggestion that migrating birds operate under energy and time constraints for only a small portion of the migratory season. During fall migration 2002, we tested the prediction that birds in better condition depart stopover sites sooner by examining the relationship between stopover duration and body condition for migrating Least Sandpipers (Calidris minutilla) at three stopover sites in the Lower Mississippi Alluvial Valley. We also tested the assumption made by the Lower Mississippi Alluvial Valley Migratory Bird Science Team that shorebirds stay in the Mississippi Valley for 10 d. The assumption of 10 d was used to estimate the amount of habitat required by shorebirds in the Mississippi Valley during fall migration; a period longer than 10 d would increase the estimate of the amount habitat required. We used multiple-day constancy models of apparent survival and program MARK to estimate stopover duration for 293 individually color-marked and resighted Least Sandpipers. We found that a four-day constancy interval and a site x quadratic time trend interaction term best modeled apparent survival. We found only weak support for body condition as a factor explaining length of stopover duration, which is consistent with findings from similar work. Stopover duration estimates were 4.1 d (95% CI = 2.8–6.1) for adult Least Sandpipers at Bald Knob National Wildlife Refuge, Arkansas, 6.5 d (95% CI = 4.9–8.7) for adult and 6.1 d (95% CI =4.2–9.1) for juvenile Least Sandpipers at Yazoo National Wildlife Refuge, Mississippi, and 6.9 d (95% CI = 5.5–8.7) for juvenile Least Sandpipers at Morgan Brake National Wildlife Refuge, Mississippi. Based on our estimates of stopover duration and the assumption made by the Lower Mississippi Alluvial Valley Migratory Bird Science Team, there is sufficient habitat in the lower Mississippi Valley to support shorebirds during fall migration.

Efficient evaluation of highly oscillatory acoustic scattering surface integrals

We consider the approximation of some highly oscillatory weakly singular surface integrals, arising from boundary integral methods with smooth global basis functions for solving problems of high frequency acoustic scattering by three-dimensional convex obstacles, described globally in spherical coordinates. As the frequency of the incident wave increases, the performance of standard quadrature schemes deteriorates. Naive application of asymptotic schemes also fails due to the weak singularity. We propose here a new scheme based on a combination of an asymptotic approach and exact treatment of singularities in an appropriate coordinate system. For the case of a spherical scatterer we demonstrate via error analysis and numerical results that, provided the observation point is sufficiently far from the shadow boundary, a high level of accuracy can be achieved with a minimal computational cost.