Aeromedical Laboratory Research Articles

Factor Analysis of Cochlear Injuries and Changes in the Electrophysiological Potentials Following Acoustic Trauma in the Guinea Pig

Following acoustic trauma in the guinea pig the changes in “threshold” and maximum voltages which can be measured for action potentials (AP) and for cochlear microphonics (CM) in different turns of the cochlea and for different test frequencies differ quantitatively. Acoustic trauma was produced by exposure to 500-cps tones. Duration and SPL of the exposures were varied inversely and approximated exposures of equal energy. All changes in electrophysiological potentials were significantly correlated, some very highly. The anatomical ratings of cochlear injury were less well correlated. A factor analysis of all variables, including measures of the traumatic exposures, showed (1) changes in CM depend on the place of measurement, (2) changes in CM do not depend on the frequency of test signal, (3) changes in AP relate best to changes in CM measured in the basal turn regardless of frequency of test signal, and (4) the scale used for rating anatomical injury in these and prior experiments does not predict changes of CM when duration and SPL of traumatic exposure are varied widely. [Supported in part by Contract No. AF 33(616)-3637, Bio-Acoustic Branch of the Aero Medical Laboratory, Wright Air Development Center.]

Some Structural and Thermal Characteristics of Snow Shelters

Reports investigations of dome-shaped shelters constructed in Alaska during winter 1955-56, some of loose, unconsolidated snow at the Arctic Aeromedical Laboratory, near Fairbanks, others of snow blocks on sea ice at Barter Island (70 08 N, 143 40 W). Pneumatic forms such as inflated weather balloons were useful, but not indispensable, in the loose snow type. Due to compaction, the density of the snow increased during construction from 0.22 gm/cu cm to 0.28 gm/cu cm and the hardness range from 8-80 gm/sq cm to 200-850 gm/sq cm Air temperatures in and outside both occupied and unoccupied shelters of this type (tabulated) demonstrate the efficacy of snow as an insulator and thermal advantages derived from ground heat. Inside temperature close to that at the ground surface, remained nearly constant (15-20 F) while outside temperatures ranged from -12 to -40 F Shelters were warmer during occupancy. In the snow-block shelters built on bare sea ice and on an 18 in deep drift, temperatures varied from 10-19 F at the top, 7-20 F in the center, and 7-18 F at the floor, while outside temperatures ranged from -2 to -5 F; thus subnivean warmth on sea ice can also be utilized. The temperature in a 2.5 ft deep trench in a drift, covered with a roof of horizontal snow blocks, was 20-24 F at the sleeping level 6 in above the floor.

Effects of Age and Sex on Pure-Tone Thresholds

Recent developments have emphasized the need for an adequate reference level from which to assess the degree of noise-induced hearing loss. The purpose of the present study was to determine the threshold of hearing for pure tones on a large sample of subjects (N = 500) drawn from a population exposed to minimal levels of industrial noise. Four age groups were studied: 18 to 24, 26 to 32, 34 to 40, and 43 to 49 years, inclusive. Threshold measurements were made from 250 to 8000 cps on a Beltone audiometer provided with PDR-8 earphones calibrated in a National Bureau of Standards Coupler 9-A. The threshold data were analyzed by age groups, ear, and sex in terms of three types of distributions: (1) original distributions which contained the data for all subjects tested; (2) screened distributions which contained the data only for subjects who passed rigid screening criteria related to otological disorders and extent of noise exposure; and (3) truncated distributions which contained only data ±15 db from the mode of the screen distributions. The results of the study indicate that in general, only minor differences (less than 5 db) exist between ears, but that women have more sensitive and less variable hearing than men. The sex difference is independent of age and appears to be more marked at the higher frequencies. Although the effects of age are clearly evident for both men and women, there is limited agreement between the curves of presbycousis of the present study and those proposed by the American Standards Association. The suggestion is offered that future audiometric standards be specified independently for men and for women according to particular age levels. [This research was supported by the United States Air Force under Contract AF 33(616)-2626 monitored by the Bio-Acoustics Branch, Aero-Medical Laboratory, Wright Air Development Center, Ohio.]

The role of clothing in prevention of thermal injury.

*Resident in Surgery, Massachusetts General Hospital, Boston, Mass. †Aero Medical Laboratory, Wright-Patterson Air Force Base, Ohio

Binaural versus Monaural Auditory Fatigue

Theoretical considerations regarding the interaction between the two ears suggest the possibility that the amount of auditory fatigue (threshold elevation) in one ear following exposure to sound will depend, in part, upon whether the exposure was directed at that ear only or at both ears. Exposures to noise and to tone were directed at either ear and at both ears of five observers, and continuous threshold recording of the absolute threshold for one ear was made following each exposure. The results indicate no significant difference in the fatiguing effect in one ear between exposures on that ear and exposures to both ears. (This research was supported in whole or in part by the U. S. Air Force under Contract No. AF33(616)-3505, monitored by Aero Medical Laboratory.)

Sound Propagation through the Atmosphere

The propagation of sound from an airborne source to the ground has been studied. The source was a propeller type airplane flown at altitudes up to 4800 ft and distances up to 9600 ft. Angles of elevation of the source with respect to the earth's surface were 2°, 5°, 15°, 30°, and 90°. The weather varied to include typical year-round conditions in the Chicago, Illinois, area and winter in Phoenix, Arizona. The noise propagated to the earth was analyzed to determine the variation in attenuation as a function of frequency and the relative position of the noise source. A statistical analysis was made to determine the effects of various weather parameters on propagation of the sound. Average values of sound attenuation were obtained. In addition, the effects of temperature, temperature gradient, humidity, wind, and wind gradient are given in an empirical formula. Propagation does not vary significantly for elevation angles between 5° and 90°, but for the 2° angle there is evidence of ground surface effects. The most important factor for minimizing the noise on the ground on a particular day was wind direction. Other meteorological conditions do not appear to be significant for controlling noise from flight operations around an airport. (Sponsored by the Aero Medical Laboratory, WCRDB, Wright-Patterson Air Force Base, Ohio.)

Cooling and Thermal Conductivity in Three Small Alaskan Mammals

Mammals are able to maintain their body temperatures in the face of cold stress through the insulation provided by their fur. In this study we explore a method for evaluating this insulating layer in dead animals and measure the modification of its effectiveness by changes in extent, thickness or air movement. These studies were supported in part under contract between the University of Wisconsin and the Alaskan Air Command, Arctic Aeromedical Laboratory, Ladd Air Force Base, Alaska, and by a research grant from the Wisconsin Alumni Research Foundation. Tundra redback voles ( Clethrionomys rutilus dawsoni ), tundra voles ( Microtus economis macfarlani ), and long-tail shrews ( Sorex cinereus hollisteri ) were trapped near Fairbanks, Alaska, in February and March of 1952. Bodies were obtained either from animals found frozen in live traps or from animals which died as a result of exposure or other laboratory tests. The temperature of the area from which the animals were taken varied from 0 to −43°C. and occasionally as low as −56°C., but the microclimate under the snow is much milder (Johnson, 1951). The five Sorex , thirteen Clethrionomys and nine Microtus studied had average weights of 2.3, 14.3 and 20.4 gm., respectively. All animals were handled as little as possible and then only by feet or tail to prevent soiling by oils, moisture, or dirt which might cause clumping and breaking of the fur. It was difficult to keep the fur clean and even the fur of live animals in captivity seemed to have an affinity for foreign material. Two methods were used to determine the rate of heat loss through the fur: (1) measuring the change in temperature of an animal body held at a constant ambient temperature; and (2) recording similar data from a fur-covered, metal cast of an animal's body. The temperatures of the …

Recovery from acoustic trauma in the guinea pig.

The LaryngoscopeVolume 67, Issue 1 p. 66-84 Article Recovery from acoustic trauma in the guinea pig†‡ Donald H. Eldredge M.D., Donald H. Eldredge M.D. St. Louis, Mo.Search for more papers by this authorWalter P. Covell M.D., Walter P. Covell M.D. St. Louis, Mo.Search for more papers by this authorHallowell Davis M.D., Hallowell Davis M.D. St. Louis, Mo.Search for more papers by this author Donald H. Eldredge M.D., Donald H. Eldredge M.D. St. Louis, Mo.Search for more papers by this authorWalter P. Covell M.D., Walter P. Covell M.D. St. Louis, Mo.Search for more papers by this authorHallowell Davis M.D., Hallowell Davis M.D. St. Louis, Mo.Search for more papers by this author First published: January 1957 https://doi.org/10.1288/00005537-195701000-00003Citations: 19 † Supported by Contract No. AF 18(600)–58 between Washington University and the Bio-Acoustic Branch of the Aero Medical Laboratory, Wright Air Development Center ‡ From the Department of Otolaryngology, Washington University School of Medicine and Central Institute for the Deaf, St. Louis, Mo AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Citing Literature Volume67, Issue1January 1957Pages 66-84 RelatedInformation

Man in a cold environment. By A. C. Burton and O. G. Edholm, Edward Arnold Ltd., London, 1955. Man in cold environment: A study in physiology. By Loren D. Carlson, Alaskan Air Command, Arctic Aeromedical Laboratory, Ladd Air Force Base, Fairbanks, Alaska. August, 1955

Man in a cold environment. By A. C. Burton and O. G. Edholm, Edward Arnold Ltd., London, 1955. Man in cold environment: A study in physiology. By Loren D. Carlson, Alaskan Air Command, Arctic Aeromedical Laboratory, Ladd Air Force Base, Fairbanks, Alaska. August, 1955

Extension of the Known Range of Marmota monax in Alaska

During the Summer of 1951, the Arctic Aeromedical Laboratory at Ladd Air Force Base, Alaska, had in its collection of experimental animals a large woodchuck ( Marmota monax ) reported to have been captured on the base. Since the range of this species had not been reported to extend this far northward, an attempt was made to collect additional specimens for study. On July 11, 1952, personnel from …

Spherical Sound Waves of Finite Amplitude

Nonlinear effects in the propagation of sound waves produced by a sinusoidally pulsating sphere have been studied theoretically. Various approximation methods have been found useful for different ranges of the parameters and at different distances from the source. Harmonic distortion generated in the field relatively near the source can be determined from a conventional perturbation solution. This solution has been developed in a form which permits numerical computation of the Fourier coefficients to terms of fourth order in the amplitude. At larger distances, this solution fails to converge, but a perturbation in terms of the characteristics of the partial differential equations is quite useful. Neglecting absorption, it is found that in spite of spherical divergence, which tends to retard the increase of distortion, the wave always evolves into an iterated shock wave at a finite distance, although a very great one for weak sources. The distance at which shocks are formed and the attenuation of the iterated shock wave as it propagates have been calculated for various examples. The work was supported by contract USAF 33 (616)-2772 with the Aero Medical Laboratory at Wright Air Development Center.

Rate of Apparent Change in a Dynamic Ambiguous Figure as a Function of Observation-Time

* Accepted for publication July 14, 1954. From the Aero Medical Laboratory. The author is indebted to Virginia W. Brown for assistance in the collection and analysis of data. 1Kate Gordon, Meaning in memory and in attention, Psychol. Rev., 10, 1903, 267-283; C. H. Graham, Area, color and brightness difference in a reversible configuration, J. Gen. Psychol., 2, 1929, 470-481; C. O. Weber, Apparent movement in Lissajou figures, this JOURNAL, 42, 1930, 647-653; M. F. Washburn, H. Mallay, and A. Naylor, The influence of the size of an outline cube on the fluctuations of its perspective, this JOURNAL, 43, 1931, 484-489; W. T. Donahue and C. H. Griffitts, The influence of complexity on the fluctuations of the illusions of reversible perspective, this JOURNAL, 43, 1931, 613-617; M. F. Washburn and Annette Gillette, Motor factors in voluntary control of cube perspective fluctuations and retinal rivalry fluctuations, this JOURNAL, 45, 1933, 315-319; H. Goldhamer, The influence of area, position, and brightness in the visual perception of a reversible configuration, this JOURNAL, 46, 1934, 189-206; M. F. Washburn, C. Reagan, and E. Thurston, The comparative controllability of the fluctuations of simple and complex ambiguous perspective figures, this JOURNAL, 46, 1934, 636638; B. R. Philip and V. R. Fisichelli, Effect of speed of rotation and complexity of pattern on the reversals of apparent movement in Lissajou figures, this JOURNAL, 58, 1945, 530-539; V. R. Fisichelli, Effect of rotational axis and dimensional variations on the reversals of apparent movement in Lissajous figures, this JOURNAL, 59, 1946, 669-675. 2I. E. Ash, Fatigue and its effects upon control, Arch. Psychol., 4, 1922 (No. 31), 1-61; N. O. Frederiksen and J. P. Guilford, Personality traits and fluctuations of the outline cube, this JOURNAL, 46, 1934, 470-474; R. W. George, The significance of the fluctuations experienced in observing ambiguous figures and in binocular rivalry, J. Gen. Psychol., 15, 1936, 39-61; W. F. Grether, J. T. Cowles, and R. E. Jones, The effect of anoxia on visual illusions, AAF Aviat. Psychol. Program Res. Reports, Report No. 19, 1947, 249-255; J. P. Guilford and K. W. Braly, An experimental test of McDougall's theory of extroversion-introversion, J. Abnorm. & Soc. Psychol., 25, 1930, 382-389; H. L. Hollingworth, Perceptual fluctuation as a fatigue index, J. Exper. Psychol., 24, 1939, 511-519; J. McV. Hunt and J. P. Guilford, Fluctuation of an ambiguous figure in dementia praecox and in manic depressive patients, J. Abnorm. & Soc. Psychol., 27, 1933, 443-452; William McDougall, Outline of Abnormal Psychology, 1926, 441-449; May Smith, A contribution to the study of fatigue, Brit. J. Psychol., 8, 1916, 327-350; M. F. Washburn, K. Keeler, K. B. New, and F. M. Parshall, Experiments on the relation of reaction-time, cube fluctuations, and mirror drawing to temperamental differences, this JOURNAL, 41, 1929, 112-117; G. K. Yacorzynski and Loyal Davis, An experimental study of the functions of the frontal lobes in man, Psychosom. Med., 7, 1945, 97-107.

Biological Effects of Sound in Mice

Local and systemic changes were studied in hairless mice following irradiation of the integument with high intensity airborne sound. Comparisons were made between effects of subthermogenic (without skin heating) and thermogenic (skin heating) sound levels. Criteria, other than morphological, used in skin analyses included cytochemical examination of skin lipids, glycogen, PAS-reactive substances, and alkaline phosphatase. Failure to induce injury or any change in skin cytochemistry after local skin irradiation daily for three months with subthermogenic sound (18 kc, 150 db) indicated that direct effects of sound are negligible at these levels. The inflammatory response of skins exposed to higher sound levels (20 kc, 160–168 db) was found to result from local absorption of sound energy and its conversion into heat. Analysis of systemic effects included studies of changes in adrenal, hemopoietic, and reproductive organs. Skin treatment with subthermogenic sound produced no appreciable systemic response. A marked systemic reaction, however, always accompanied sound induced skin burns. Additional studies on effects of auditory stimulation on adrenals and eosinophils showed that prolonged exposure of mice to loud noise fields (10–20 kc, 110 db) proved to elicit only a mild systemic response. This work was sponsored in part by the Aero Medical Laboratory, Wright-Patterson Air Force Base, Dayton, Ohio, under contract No. AF 33(616)-2505

Hematological Studies on Mammals from Alaska

It is evident, according to Downey (1938), that hematological studies on mammals other than the common laboratory and domestic forms are relatively scarce. The comprehensive tabulations in the appendix of Wintrobe's (1953) work on hematology show the dearth of information in this field. During the course of a research problem dealing with the physiology of arctic animals, considerable hematological data were obtained from a variety of mammalian specimens. The work of Slane and Wilber (1952) on the hematology of the red backed mouse, Clethrionomys dawsoni from central Alaska, is the only recent contribution to our knowledge of blood cells in wild Alaskan mammals. In order to keep interested investigators informed, this report on blood counts, differentials and erythrocyte measurements from a number of mammals collected in Alaska is presented. Species .—The following species were studied in this investigation: Hudson Bay ground squirrel, Citellus parryii parryii ; Yukon ground squirrel, Citellus osgoodi ; Alaska red squirrel, Sciurus hudsonicus petulans ; MacFarlane meadow mouse, Microtus macfarlani ; black bear, Ursus americanus ; ochraceous wood-chuck, Marmota monax ochracea ; snowshoe hare, Lepus americanus; cottontail rabbit, Sylvilagus sp .; Richardson weasel, Mustela erminea richardsonii ; north-western muskrat, Ondatra zibethica spatulata ; Alaska porcupine, Erethizon epixan thum myops . Field and laboratory work .—During the summer of 1951, red squirrels, meadow mice, woodchucks, snowshoe hares and muskrats were collected at various places in central Alaska. Some ground squirrels, porcupines, weasels, rabbits and the black bear were supplied from the menagerie at the Arctic Aeromedical Laboratory, Ladd Air Force Base, Fairbanks, Alaska. Blood samples for counts and differentials were generally taken by bleeding an animal from a digit. The blood smears were stained with Wright's or Giemsa's technique. Erythrocyte measurements were made using a calibrated ocular micrometer. This research project was supported in part by …

Accommodative response of the eye to electrical stimulation of the ciliary ganglion in cats.

School of Optometry, University of California, Berkeley 1st Lieutenant Aero Medical Laboratory, Directorate of Research Wright-Patterson Air Force Base, Ohio Cleveland, Ohio *Read before the annual meeting of the American Academy of Optometry, Chicago, Illinois, December 7, 1953. For publication in the March, 1954, issue of the American Journal of Optometry and Archives of American Academy of Optometry. †Optometrist. Ph.D., Member of faculty. Fellow, American Academy of Optometry. ‡Doctor of Veterinary Medicine. §Doctor of Veterinary Medicine.

The organ of Corti by phase contrast microscopy.

The LaryngoscopeVolume 63, Issue 1 p. 1-17 Article The organ of corti by phase contrast microscopy† Y. Katsuki M.D., Y. Katsuki M.D. Tokyo, Japan On leave of absence from Tokyo Medical and Dental University for study at Central Institute for the Deaf.Search for more papers by this authorW. P. Covell M.D., W. P. Covell M.D. St. Louis, Mo.Search for more papers by this author Y. Katsuki M.D., Y. Katsuki M.D. Tokyo, Japan On leave of absence from Tokyo Medical and Dental University for study at Central Institute for the Deaf.Search for more papers by this authorW. P. Covell M.D., W. P. Covell M.D. St. Louis, Mo.Search for more papers by this author First published: January 1953 https://doi.org/10.1288/00005537-195301000-00001Citations: 22 † Supported by Contract AF 18(600)-58 between Washington University, St. Louis, Mo., and the Aero-Medical Laboratory, Wright-Patterson Air Force Base, Ohio. AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Volume63, Issue1January 1953Pages 1-17 RelatedInformation

The body surface area of Eskimos as determined by the linear and the height-weight formulas.

American Journal of Physical AnthropologyVolume 10, Issue 4 p. 419-426 Article The body surface area of Eskimos as determined by the linear and the height-weight formulas Kaare Rodahl Jr., Kaare Rodahl Jr. Department of Physiology, Arctic Aeromedical Laboratory, Fairbanks, Alaska The author is greatly indebted to Dr. E. F. DuBois for his valuable criticism and advice throughout this study, and for his personal supervision during the initial measurements. He is also indebted to Lt. Col. A. Karstens, Commanding Officer of the Arctic Aeromedical Laboratory, for his valuable support.Search for more papers by this author Kaare Rodahl Jr., Kaare Rodahl Jr. Department of Physiology, Arctic Aeromedical Laboratory, Fairbanks, Alaska The author is greatly indebted to Dr. E. F. DuBois for his valuable criticism and advice throughout this study, and for his personal supervision during the initial measurements. He is also indebted to Lt. Col. A. Karstens, Commanding Officer of the Arctic Aeromedical Laboratory, for his valuable support.Search for more papers by this author First published: December 1952 https://doi.org/10.1002/ajpa.1330100405Citations: 7 AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Volume10, Issue4December 1952Pages 419-426 RelatedInformation

Collections of Ectoparasitic Mites from Alaska

This report on ectoparasitic mites from Alaska is presented to supplement the few published accounts of mites from the territory (see references). All species concerned are members of the family LAELAPTIDAE. Specimens reported were obtained from three sources: Rocky Mountain Laboratory of the United States Public Health Service, through Mr. Glen M. Kohls; United States National Museum, through Dr. E. W. Baker; and Arctic Aeromedical Laboratory of the United States Air Force, through Captain John M. Geary. Among the specimens sent by Mr. Kohls were three collections made on Nunivak Island by personnel of the Arctic Health Research Center of the United States Public Health Service at Anchorage. Unmounted specimens were prepared for study by enlisted personnel of the survey section, 498th Preventive Medicine Company, Fort Sam Houston, Texas. Specimens reported in this paper were taken from rodents and birds at several widely separated localities from Nunivak Island off the coast of southwestern Alaska to Umiat and Barter Island far above the Arctic circle. Eight species are represented in these collections. In the list which follows, Rocky Mountain Laboratory is abbreviated as RML, and Arctic Health Research Center is abbreviated as AHRC. Identified specimens have been returned to the institutions from which they were obtained.

Applied anthropometry of the hand.

American Journal of Physical AnthropologyVolume 10, Issue 2 p. 209-216 Article Applied anthropometry of the hand† Gilbert S. Daniels, Gilbert S. Daniels Anthropology Unit, Biophysics Branch, Aero Medical Laboratory, Wright Air Development Center, Wright-Patterson Air Force Base, Dayton, Ohio 2nd Lt., USAF (MSC).Search for more papers by this authorH. T. E. Hertzberg, H. T. E. Hertzberg Anthropology Unit, Biophysics Branch, Aero Medical Laboratory, Wright Air Development Center, Wright-Patterson Air Force Base, Dayton, OhioSearch for more papers by this author Gilbert S. Daniels, Gilbert S. Daniels Anthropology Unit, Biophysics Branch, Aero Medical Laboratory, Wright Air Development Center, Wright-Patterson Air Force Base, Dayton, Ohio 2nd Lt., USAF (MSC).Search for more papers by this authorH. T. E. Hertzberg, H. T. E. Hertzberg Anthropology Unit, Biophysics Branch, Aero Medical Laboratory, Wright Air Development Center, Wright-Patterson Air Force Base, Dayton, OhioSearch for more papers by this author First published: June 1952 https://doi.org/10.1002/ajpa.1330100218Citations: 5 † Presented at the twentieth annual meeting of the american association of physical anthropologists, march, 1951, at the university of michigan, ann arbor. AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Citing Literature Volume10, Issue2June 1952Pages 209-216 RelatedInformation

The Arctic Aeromedical Laboratory at Fairbanks, Alaska

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