Search NASA⌕ Search

SEARCH · Search NASA

Results for “EAR”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 163 records · Page 9
All sourcesNASA NTRSDOE OSTI
NASA NTRS1975

The auditory neural network in man

The principles of anatomy and physiology necessary for understanding brain wave recordings made from the scalp are briefly discussed. Brain waves evoked by sounds are then described and certain of their features are related to the physical aspects of the stimulus and the psychological state of the listener. It is proposed that data obtained through probes located outside the head can reveal a large amount of detail about brain activity. It is argued that analysis of such records enables one to detect the response of the nervous system to an acoustic message at the moment of its inception at the ear, and to follow the progress of the acoustic message up through the various brain levels as progressively more complex operations are performed upon it. Even those brain events responsible for the highest level of signal processing - distinguishing between similar signals and making decisions about them - seem to generate characteristic and identifiable electrical waves.

Galambos, R.↗
NASA NTRS1978

Cable-clamp installation tool

Tiny vise simplifies installation of cable clamps in confined spaces. As thumbscrew is tightened, ears of clamps are forced together, and bolt passes through all lugs and into hole in stationary jaw.

Noel, M. B.↗
NASA NTRS1976

Effect of ambient temperature on the thermal profile of the human forearm, hand, and fingers

Forearm, hand, and finger skin temperatures were measured on the right and left sides of seven resting men. The purpose was to determine the bilateral symmetry of these segmental temperature profiles at ambient temperatures from 10 to 45 C. Thermistors placed on the right and left forearms, hands, and index fingers were used to monitor the subjects until equilibration was reached at each ambient temperature. Additionally, thermal profiles of both hands were measured with copper-constantan thermocouples. During one experimental condition (23 C ambient), rectal, ear canal, and 24 skin temperatures were measured on each subject. Average body and average skin temperatures are given for each subject at the 23 C ambient condition. Detailed thermal profiles are also presented for the dorsal, ventral, and circumferential left forearm, hand, and finger skin temperatures at 23 C ambient. No significant differences were found between the mean skin temperatures of the right and left contralateral segments at any of the selected ambient temperatures.

Montgomery, L. D.↗
NASA NTRS1977

Some physiological effects of alternation between zero gravity and one gravity

The anatomy and physiology of the healthy vestibular system and the history of its study, maintenance of muskuloskeletal fitness under low-gravity conditions, tests of motion sickness, and data and techniques on testing subjects in a slow rotation room, are covered. Components of the inner ear labyrinth and their behavior in relation to equilibrium, gravity and inertial forces, motion sickness, and dizziness are discussed. Preventive medicine, the biologically effective force environment, weightlessness per se, activity in a weightless spacecraft, exercizing required to maintain musculoskeletal function, and ataxia problems are dealt with.

Graybiel, A.↗
NASA NTRS1978

Structural and Functional Organization of the Vestibular Apparatus in Rats Subjected to Weightlessness for 19.5 Days Aboard the Kosmos-782 Satellite

The vestibular apparatus was investigated in rats subjected to weightlessness for 19.5 days. The vestibular apparatus was removed and its sections were fixed in a glutaraldehyde solution for investigation by light and electron microscopes. Structural and functional charges were noted in the otolith portions of the ear, with the otolith particles clinging to the utricular receptor surface and with the peripheral arrangement of the nucleolus in the nuclei of the receptor cells. It is possible that increased edema of the vestibular tissue resulted in the destruction of some receptor cells and in changes in the form and structure of the otolith. In the horizontal crista, the capula was separated.

Vinnikov, Y. A.↗
NASA NTRS1978

AGRESTE project: Agricultural resources investigations in northern Italy and southern France

The author has identified the following significant results. Recognition of rice varieties at the flowering stage by using airborne scanner data at low altitude (1500 m) seems to be feasible. The accuracies obtained on a reduced test area (3 sq km) range from 65% to 83%. Variations of a single cultural factor, such as nitrogen fertilization, induce variations of the total rice biomass at harvest, which can be correlated closely to the values of the reflectance ratio at earing. When grain production is correlated to total biomass, prediction of yield can be achieved based on reflectance data measured two months before harvest.

Berg, A.↗
NASA NTRS1978

The effective acoustic environment of helicopter crewmen

Methods of measuring the composite acoustic environment of helicopters in order to quantify the effective acoustic environment of the crewmen and to assess the real acoustic hazards of the personnel are examined. It is indicated that the attenuation characteristics of the helmets and hearing protectors and the variables of the physiology of the human ear be accounted for in determining the effective acoustic environment of Army helicopter crewmen as well as the acoustic hazards of voice communications systems noise.

Camp, R. T., Jr.↗
NASA NTRS1980

Loudness enhancement and decrement in four paradigms

When one tone burst (the conditioner) preceeds another (the target) by 100 ms, target loudness is enhanced if the conditioner is more intense and decreased if it is less intense. We show here that similar loudness enhancements and decrements occur when the conditioner follows the target. In all instances, monaural loudness enhancements (in which the conditioner and target are delivered to the same ear) are greater than the dichotic enhancements (in which the conditioner is presented contralaterally), but the decrements, which are smaller than the enhancements, are similar in magnitude. Loudness enhancements and decrements are similar to sequential loudness effects and central tendency effects; the major difference is the relatively very large increases in loudness obtainable in loudness enhancement experiments. We outline a mechanism to account for these loudness phenomena and suggest that this mechanism is responsible for similar perceptual effects that occur in other stimulus dimensions and modalities.

Elmasian, R.↗
NASA NTRS1981

Stability of individual loudness functions obtained by magnitude estimation and production

A correlational analysis of individual magnitude estimation and production exponents at the same frequency is performed, as is an analysis of individual exponents produced in different sessions by the same procedure across frequency (250, 1000, and 3000 Hz). Taken as a whole, the results show that individual exponent differences do not decrease by counterbalancing magnitude estimation with magnitude production and that individual exponent differences remain stable over time despite changes in stimulus frequency. Further results show that although individual magnitude estimation and production exponents do not necessarily obey the .6 power law, it is possible to predict the slope of an equal-sensation function averaged for a group of listeners from individual magnitude estimation and production data. On the assumption that individual listeners with sensorineural hearing also produce stable and reliable magnitude functions, it is also shown that the slope of the loudness-recruitment function measured by magnitude estimation and production can be predicted for individuals with bilateral losses of long duration. Results obtained in normal and pathological ears thus suggest that individual listeners can produce loudness judgements that reveal, although indirectly, the input-output characteristic of the auditory system.

Hellman, R. P.↗
NASA NTRS1981

Reissner's membrane and the spiral ligament in normal rats and those treated with ethacrynic acid

A description is presented of recent ultrastructural findings in Reissner's membrane and the spiral ligament in rats treated daily with ethacrynic acid during the 2nd and 3rd weeks of postnatal life, a period of final maturation of the inner ear and its fluids. A distension of Reissner's membrane in every cochlear turn, indicative of mild endolymphatic hydrops, was found to occur in animals that received a higher dose of ethacrynic acid. Ultrastructurally, the cytoplasm of the epithelial cells of Reissner's membrane showed increased electron density after treatment with ethacrynic acid. This increase was most pronounced in animals treated with a greater quantity of the drug. The epithelial cells had similar ultracellular features throughout except that the cells were much thinner in the region of maximal distension.

Ross, M. D.↗
NASA NTRS1981

Ocular torsion on earth and in weightlessness

Otolith function is studied by means of measurements of ocular torsion under various acceleration environments on earth and in weightlessness. Photographic measurements of ocular torsion as indicated by the rotation of landmarks on the iris with respect to head-fixed fiducial marks were obtained in subjects undergoing horizontal linear acceleration in a ground-based version of the space sled, lateral acceleration from weightlessness during pullout from the free-fall portion of parabolic flight, and optokinetic stimulation about the roll axis in the supine position in the laboratory and during weightlessness. The responses of ocular torsion to horizontal acceleration are in agreement with a simple low-order linear system with a dominant time constant of 0.33 sec, with a transfer function fit by a model with a pure delay of 0 to 400 msec and a first-order lag. In the pullout experiment, torsion was not observed in response to the onset of acceleration in the right-ear-down position, although it was present in response to the lateral stimulus. Results of the roll vection experiments indicate the independence of ocular torsion and visually induced tilt. In addition, an automatic video system using a soft contact lens target is presented which has been developed for ocular torsion measurements.

Young, L. R.↗
NASA NTRS1982

Measurement of cardiopulmonary performance during acute exposure to a 2440-m equivalent atmosphere

Each of 20 subjects (ranging in age from 18 to 38 years, 15 being male, five female) was given two Bruce Protocol symptom-limited maximum treadmill stress tests, breathing sea-level compressed air (20.9% O2) for one test and a 2440-m equivalent (15.5% O2) for the other. A significant difference was found to exist between measured VO2 max (p less than 0.0002) and exercise time (p less than 0.0004) for the two conditions. No significant differences were observed in heart rate or the recovery time to a respiratory quotient of less than 1. Hemoglobin saturation, as measured by an ear oximeter, averaged 95% for sea-level and 91% for the 2440-m equivalent gases. These results support a 2440-m equivalent contingency atmosphere in the Space Shuttle prior to donning a low-pressure suit for the purpose reducing nitrogen washout times.

Levitan, B. M.↗
NASA NTRS1982

Measurement of ocular counterrolling /OCR/ by polarized light

The assessment of the activation of the otolith gravitoinertial sensors in the vestibular system of the inner ear may be accomplished by observing the occular counterrolling (OCR) movements which rotate the eyes about the line of sight. A method is presented for the continuous measurement of OCR by means of polarized light, a system of polarizers, and a contact lens. A polarized hard contact lens is placed between two soft lenses before application to the eye, and the measured phase difference between the incident rotating polarized light and the reflected light from this lens provides readings uncontaminated by other eye movement modes.

Kenyon, R. V.↗
NASA NTRS1982

Daily rhythms of activity and temperature of Macaca nemestrina

The activity and temperature rhythms of pig-tailed macaques (Macaca nemestrina) maintained in LD 16:8 at 25 C in specially designed restraint chairs have been examined. Activity was monitored via a sensor that was attached to the restraint chair. Temperature was monitored at the axilla, ankle and ear. All variables showed prominent day-night variations, and except for ankle temperature, had highest values during the daytime. These results show that the regulation of the daily rhythm of body temperature involves anatomical sites that are utilized in a temporally distinct fashion.

Sulzman, F. M.↗
NASA NTRS1983

Interrelated striated elements in vestibular hair cells of the rat

A series of interrelated striated organelles in types I and II vestibular hair cells of the rat which appear to be less developed in cochlear hair cells have been revealed by unusual fixation procedures, suggesting that contractile elements may play a role in sensory transduction in the inner ear, especially in the vestibular system. Included in the series of interrelated striated elements are the cuticular plate and its basal attachments to the hair cell margins, the connections of the strut array of the kinociliary basal body to the cuticular plate, and striated organelles associated with the plasma membrane and extending below the apical junctional complexes.

Ross, M. D.↗
NASA NTRS1983

Late skin damage in rabbits and monkeys after exposure to particulate radiations

Preliminary results are reported of experiments on the late effects of exposure to particulate radiations on stem cell populations. Skin biopsies were taken from the ears of rabbits irradiated 2-5 years previously with 530 MeV/amu Ar ions (LET 90 keV/micron), or 365 MeV/amu Ne ions (LET 35 keV micron), and from the chests and inner thighs of rhesus monkeys irradiated 16-18 years previously with 32-MeV protons (LET about 1.2 keV/micron). Skin fibroblast cultures obtained from the biopsy samples in rabbits were observed to undergo dose-dependent decreases in in vitro life span, with estimated survival curves showing the effects of Ar-ion irradiation to be more severe than those of Ne-ion irradiation. In addition, the healing of the biopsy wound was observed to become slower as radiation dose increased. In the monkey, radiation reduced the average number of fibroblasts at the time of cessation of growth in culture. Results thus demonstrate the capacity of skin sampling to reveal stem cell destruction, and have important implications for astronauts and other persons at risk of particle exposure with regard to healing responses to trauma or surgery.

Bergtold, D. S.↗