Speech discrimination of place-loaded Modified Rhyme test words in speech-babble and cafeteria noise by elderly hearing-impaired subjects was measured. The stimuli were presented under the following conditions: (1) monotic: the signal was presented to the preferred ear; (2) low-frequency attenuated: the frequency band below 1,000 Hz was attenuated by 5, ...

Heterodyne difference frequency measurements between a (13)CO(2) laser and a diode laser tuned (and in most cases locked) to the peaks of OCS absorption lines have been used to improve frequency calibration tables in the 860-cm(-1) region by factors of 20-50. Measurements have been made on the vibrational transitions 10(0)0-00(0)0, ...

Compound action potentials (AP) were recorded under various stimulus conditions in 31 guinea pigs. Stimulus attenuation, decrease of inter-stimulus interval, increase of the level of a continuous wide-band noise maker, and lowering the animal's temperature all resulted in a drop of the AP amplitude and an increase in latency. A ...

Auditory adaptation effects were measured for narrow bands of noise both within and outside of the critical band for 1 000 Hz. In keeping with previous research, a pure-tone condition resulted in more adaptation than any of the noise band conditions. However, as the noise bands were increased in width, ...

Compression and noncompression amplification were compared for a range of conditions. The noncompression conditions included flat-frequency response and "LDL frequency response," with and without peak clipping. The compression conditions included a single-band compression system and two combinations of a two-channel compression system. The LDL frequency response was obtained by finding ...

Five monaural chinchillas were trained with a method of shock-avoidance conditioning to respond to silent intervals, or gaps, in an otherwise noise. The noise was low-pass filtered at either 10 or 6 kHz and presented at six intensities ranging between 23- and 77- dB sound-pressure level (SPL). Gap detection thresholds ...

The acuity of auditory localization in Old World monkeys (Macaca) was determined psychophysically for 44 noise bands graded in bandwidth and center frequency. The acuity of localization was assessed through the method of constant stimuli under free-field conditions in an anechoic chamber. Monkeys were trained through positive-reinforcement operant-conditioning procedures to ...

In identifying the criteria which influence soldering distortion, the results of this study indicate the following: 1. Linear distortion identified at the investment phase (a net increase in gap distance) is due to setting expansion of the plaster and soldering investment. 2. The linear distortion identified at the soldering phase ...

Discharge rate was measured as a function of spectral level for noise bursts of one bandwidth and center frequency. Such rate-level functions were measured for a number of bandwidths; either the low- or high-cutoff frequencies were set at fiber characteristic frequency (CF). Rate-level functions were also measured, simultaneously, for single ...

A model of "reflection" was developed in a sucrose gap preparation of Purkinje fibers. In this preparation, a driven impulse on the proximal side of a sucrose gap is electrotonically transmitted after a delay to the tissue distal to the gap. When the delay is long enough, electrotonic transmission in ...

Loudness discomfort levels (LDL's) were obtained on 19 normal-hearing subjects with 18 different stimuli using a simple up-down adaptive procedure. The stimuli included five pure tones, five one-third octave bands of noise, five one-third octave bands of filtered multi-talker babble, wide-band noise, spondaic words, and sentences. Results indicated there was ...

The relative frequency selectivity of the internal auditory filters, as measured by critical bands or critical ratios, and psychophysical tuning curves, was compared in an avian species (parakeet) and human listeners. The results indicate that the critical band predicts the frequency selectivity of psychophysical tuning curves and vice versa. These ...

To investigate consonant information in low frequencies, a low-frequency band which contains negligible consonant information in isolation was added to a high-frequency band. There was a significant increase from the high-frequency band-alone score for normal-hearing subjects when the bands were presented at favorable low-frequency/high-frequency bands sensation levels either to the ...

The electrotonic interactions of a parasystolic pacemaker with ventricular responses to the normal pacemaker across an area of depressed excitability were simulated in a model consisting of strands of canine Purkinje fibers mounted in a sucrose gap preparation. Experiments were conducted to study the patterns of ectopic activity that result ...

The detection threshold of a single gap in white noise was measured as a function of the gap duration. The results can be described with an auditory integration time of about 25 ms. This value is much larger than the 3--4 ms usually found in experiments on auditory temporal integration. ...

Derived narrow-band action potential latencies increase monotonically with decreasing central frequency, and can be interpreted as reflecting the traveling wave delay in the cochlea. It was found that, for recruiting human ears with average flat hearing losses around 40 dB, this accumulating latency increase was smaller than for normal ears. ...

Twenty patients with presbycusis and a rather flat audiometric pattern had critical band estimation performed by the method of loudness summation, using noise bands centred around 1 kHz. The pooled data indicated a normal critical band both in patients with a hearing loss less than 50 dB HL and in ...

The group-specific component (Gc) was examined in a sample of 78 chimpanzees (Pan troglodytes). With isoelectric focusing followed by immunofixation, two different phenotypes are observed. They both differ from the Gc types observed in man. Two alleles are postulated, one coding for a double-band component, the other coding for a ...

A quasi-optical diplexer for injection of signal and local oscillator frequencies into a mixer at millimeter wave-lengths is described. The diplexer accepts both image and signal bands, presents low loss at both the signal and local oscillator frequencies and rejects local oscillator noise at the signal frequency. The configuration of ...

Experienced Ss identified (2IFC) the signal complex that contained a gap. When the complexes were of the same frequency, gap detection remained constant over the durations employed (up to 300 msec). When duration of the signal was 10 msec no changes in gap threshold occurred over the range of frequency ...

The purpose of this study was twofold: to determine if the measured loudness level of a signal depends on the standard stimulus used and to measure loudness as a function of the number of components in a wide-band signal. The stimuli were a pure tone, tone complexes with frequency separations ...

Derived cochlear nerve and brainstem evoked responses (CBER) were obtained for various frequency bands and were masked using special maskers. These maskers were designed to match exactly the intensity/frequency profile characteristics of the bands from which derived CBERs were obtained. Derived responses were markedly affected whenever the masker frequency limits ...

A compact narrow band lamp for high intensity irradiation has been developed. It consists of a high-pressure mercury lamp, a shutter and water cooled filters for spectral isolation of the light. A mixing device permits simultaneous irradiation with two different wavelenghts by using two lamps. The spectral distribution of the ...

A new and powerful procedure for determining frequency analysis in the auditory system, as evidence by the critical band, is described. The onset time difference, delta T, needed to lateralize 30-msec tone bursts toward the leading ear was measured as a function of the frequency difference, delta F, between the ...

The nature of bladder electrical activity was investigated in anaesthetised cats and 1 baboon. A time-locked muscle response to sacral ventral root stimulation was most clearly detected within a 10-40 Hz frequency band, the response preceding the rise in intravesical pressure. During reflex voiding only activity in the 10-40 Hz ...

Spruce leaves greened in darkness were devoid of three of the five thermoluminescence bands found for mature leaves. These bands were developed rapidly by exposure of the dark-grown leaves to continuous light. The development of these bands was studied by illumination with repetitive flashes at varied intervals. Flashes at intervals ...

Threshold measurements have been made on random patterns that have been computer filtered to contain only certain spatial frequencies. The dependence of threshold on the spatial-frequency distribution of the energy in the patterns was measured. The results indicate that the visibility of an unstructured pattern is dependent on the spatial-frequency ...

A comparison was made of the effect on consonant-recognition scores when a low-frequency passband and a high-frequency passband were presented to either the same ear or opposite ears of hearing-impaired subjects. The Fairbanks Rhyme Test was filtered into two bands-240-480 Hz (low band) and 1020-2040 Hz (high band). The high ...

Children with sharply sloping audiometric configurations were examined audiometrically using pure tones and narrow bands of noise with equivalent bandwidths but varying in filter slope. Thresholds were established at the octave frequencies from 500 to 5000 Hz. The results indicated more sensitive thresholds for narrow bands of noise with threshold ...

The characteristics of the critical masking band, that spectral region of a wideband noise that is effective in masking a pure-tone signal, were inferred by measuring detectability (d) for tonal signals as a function of the cutoff frequency of a low-pass or high-pass noise masker. As the cutoff frequency of ...

We have built an instrument that counts pulses from photomultipliers that look at four bands of solar continuum, recording the changes in intensity during an eclipse. We use a plywood spectrograph to select an ultraviolet band and interference filters for the others. The number of counts seen in 1/20 sec ...

Light-dependent regulation of cell cycle progression in the marine cyanobacterium Synechococcus strain WH-8101 was demonstrated through the use of flow cytometry. Our results show that, similar to eucaryotic cells, marine Synechococcus spp. display two gaps in DNA synthesis, at the beginning and at the end of the cell cycle. Progression ...

Radio interferometry with independent high-precision clocks, without a high-frequency communication channel between the stations, is now a possibility. It allows the stations to be as far apart as the earth can accommodate. This then makes the radio band from 10- to 60-centimeters wavelength the best frequency range for high-precision angular ...

The heterogeneity of the peroxidases in peas was examined by starch gel electrophoresis. Comparisons were made between tall and dwarf cultivars and among organ systems developed in light and darkness. Isoperoxidase bands could be grouped as cathodic, anodic and near-neutral (at pH 9.0) types. The cathodic set stained well with ...

Experiments were done on the skin with shearing forces, vibrations, and heat stimuli and on the tongue with taste stimuli to show that the well known Mach bands are not exclusively a visual phenomenon. On the contrary, it is not difficult to produce areas of a decreased sensation magnitude corresponding ...

The luminous band around the horizon noted by J. Glenn in the first U.S. manned orbital flight is attributable to airglow. Dip-of-the-horizon measurements on the star gamma Ursae Majoris showed that the band is centered at an elevation of 91 kilometers or somewhat higher. The edge-on brightness of the airglow ...

In an operant-conditioning study, a bull shark responded to signals at frequencies between 100 and 1500 cy/sec. In its band of greatest sensitivity (400 to 600 cy/sec), it discriminated, from high-level ambient noise, signals of amplitudes which the apparatus could not measure.