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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.

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At least 235 records · Page 13
All sourcesNASA NTRSDOE OSTI
NASA NTRS1988

The Franco-American macaque experiment

The details of studies to be carried out jointly by French and American teams on two rhesus monkeys prepared for future experiments aboard the Space Shuttle are discussed together with the equipment involved. Seven science discipline teams were formed, which will study the effects of flight and/or weightlessness on the bone and calcium metabolism, the behavior, the cardiovascular system, the fluid balance and electrolytes, the muscle system, the neurovestibular interactions, and the sleep/biorhythm cycles. New behavioral training techniques were developed, in which the animals were trained to respond to behavioral tasks in order to measure the parameters involving eye/hand coordination, the response time to target tracking, visual discrimination, and muscle forces used by the animals. A large data set will be obtained from different animals on the two to three Space Shuttle flights; the hardware technologies developed for these experiments will be applied for primate experiments on the Space Station.

Cipriano, Leonard F.↗
NASA NTRS1988

Eye and head motion during head turns in spaceflight

Eye-head motion was studied pre-, in- and postflight during single voluntary head turns. A transient increase in vestibulo-ocular reflex (VOR) gain occurred early in the flight, but later trended toward normal. This increased gain was produced by a relative increase in eye counterrotation velocity. Asymmetries in gain with right and left turns also occurred, caused by asymmetries in eye counterrotation velocities. These findings were remarkably similar to those from Soviet primate studies using gaze fixation targets, except the human study trended more rapidly toward normal. These findings differ substantially from those measuring VOR gain by head oscillation, in which no significant changes were found inflight. No visual disturbances were noted in either test condition or in normal activities. These head turn studies are the only ones to date documenting any functional change in VOR in weightlessness.

Thornton, William E.↗
NASA NTRS1989

Note on hand use in the manipulation of joysticks by rhesus monkeys (Macaca mulatta) and chimpanzees (Pan troglodytes)

MacNeilage et al. (1987) have proposed that nonhuman primate handedness may be contingent on the specific task requirements, with visual-spatial tasks yielding left-hand preferences and fine-motor tasks producing right-hand preferences. This study reports hand preferences in the manipulation of joysticks by 2 rhesus monkeys and 3 chimpanzees. Reach data were also collected for comparison with preference data for manipulation of the joystick. The data indicated that all 5 subjects demonstrated significant right-hand preferences in manipulating the joystick. In contrast, no significant hand preferences were found for the reach data. Reaction-time data also indicated that the right hand could perform a perceptual-motor task better than the left hand in all 5 subjects. Overall, the data indicate that reach tasks may not be sensitive enough measures to produce reliable hand preferences, whereas tasks that assess fine-motor control produce significant hand preferences.

Hopkins, William D.↗
NASA NTRS1989

Rhesus monkeys (Macaca mulatta), video tasks, and implications for stimulus-response spatial contiguity

Recent reports support the argument that the efficiency of primate learning is compromised to the degree that there is spatial discontiguity between discriminands and the locus of response. Experiments are reported here in which two rhesus monkeys easily mastered precise control of a joystick to respond to a variety of computer-generated targets despite the fact that the joystick was located 9 to 18 cm from the video screen. It is argued that stimulus-response contiguity is a significant parameter of learning only to the degree that the monkey visually attends to the directional movements of its hand in order to displace discriminands. If attention is focused on the effects of the hand's movement rather than on the hand itself, stimulus-response contiguity is no longer a primary parameter of learning. The implications of these results for mirror-guided studies are discussed.

Rumbaugh, Duane M.↗
NASA NTRS1990

Pyramidal Image-Processing Code For Hexagonal Grid

Algorithm based on processing of information on intensities of picture elements arranged in regular hexagonal grid. Called "image pyramid" because image information at each processing level arranged in hexagonal grid having one-seventh number of picture elements of next lower processing level, each picture element derived from hexagonal set of seven nearest-neighbor picture elements in next lower level. At lowest level, fine-resolution of elements of original image. Designed to have some properties of image-coding scheme of primate visual cortex.

Watson, Andrew B.↗
NASA NTRS1989

Effect of contrast on the perception of direction of a moving pattern

A series of experiments examining the effect of contrast on the perception of moving plaids was performed to test the hypothesis that the human visual system determines the direction of a moving plaid in a two-staged process: decomposition into component motion followed by application of the intersection-of-contraints rule. Although there is recent evidence that the first tenet of the hypothesis is correct, i.e., that plaid motion is initially decomposed into the motion of the individual grating components, the nature of the second-stage combination rule has not yet been established. It was found that when the gratings within the plaid are of different contrast the preceived direction is not predicted by the intersection-of-constraints rule. There is a strong (up to 20 deg) bias in the direction of the higher-constrast grating. A revised model, which incorporates a contrast-dependent weighting of perceived grating speed as observed for one-dimensional patterns, can quantitatively predict most of the results. The results are then discussed in the context of various models of human visual motion processing and of physiological responses of neurons in the primate visual system.

Stone, L. S.↗
NASA NTRS1989

Non-contact temperature measurements in support of microgravity combustion experiments

Recent conceptual advances in the understanding of combustion science fundamentals in the context of microgravity processes and phenomenology have resulted in an increased demand for diagnostic systems of greater sophistication. Owing primarily to the severe operational constraints that accompany the space flight environment, measurement systems to date remain fairly primative in nature. Qualitative pictures provided by photographic recording media comprise the majority of the existing data, the remainder consisting of the output of conventional transducers, such as thermocouples, hot wires, and pressure transducers. The absence of the rather strong influence of buoyant convection renders microgravity combustion phenomena more fragile than their 1-G counterparts. The emphasis was placed on nonperturbing optical diagnostics. Other factors such as limited supplies of expendable reactants, and periods of microgravity time of sufficient duration, coupled with more fundamental questions regarding inherent length and time scales and reproducibility have favored multipoint or multidimensional techniques. While the development of optical diagnostics for application to combustion science is an extremely active area at present, the peculiarities of space flight hardware severely restrict the feasibility of implementing the majority of techniques which are being utilized in terrestrial applications. The additional requirements for system reliability and operational simplicity have tended to promote somewhat less commonly emphasized techniques such as refractive index mapping and molecular Rayleigh scattering, which are briefly discussed.

Greenberg, Paul S.↗
NASA NTRS1990

Pyramid image codes

All vision systems, both human and machine, transform the spatial image into a coded representation. Particular codes may be optimized for efficiency or to extract useful image features. Researchers explored image codes based on primary visual cortex in man and other primates. Understanding these codes will advance the art in image coding, autonomous vision, and computational human factors. In cortex, imagery is coded by features that vary in size, orientation, and position. Researchers have devised a mathematical model of this transformation, called the Hexagonal oriented Orthogonal quadrature Pyramid (HOP). In a pyramid code, features are segregated by size into layers, with fewer features in the layers devoted to large features. Pyramid schemes provide scale invariance, and are useful for coarse-to-fine searching and for progressive transmission of images. The HOP Pyramid is novel in three respects: (1) it uses a hexagonal pixel lattice, (2) it uses oriented features, and (3) it accurately models most of the prominent aspects of primary visual cortex. The transform uses seven basic features (kernels), which may be regarded as three oriented edges, three oriented bars, and one non-oriented blob. Application of these kernels to non-overlapping seven-pixel neighborhoods yields six oriented, high-pass pyramid layers, and one low-pass (blob) layer.

Watson, Andrew B.↗
NASA NTRS1990

Effect of contrast on the perceived direction of a moving plaid

A series of experiments examining the effect of contrast on the perception of moving plaids is performed. This was done to test the hypothesis put forth by Adelson and Movshon (1982) that the human visual system determines the direction of a moving plaid in a two-staged process: decomposition into component motion followed by application of the intersection of constraints rule. When the gratings within the plaid are of different contrast, the perceived direction is not predicted by the intersection of constraints rule. There is a strong (up to 20 deg) bias in the direction of the higher-contrast grating. A revised model, which incorporates a contrast-dependent weighting of perceived grating speed as observed for one-dimensional patterns (Thompson, 1982), can quantitatively predict most of the results. Results are discussed in the context of various models of human visual motion processing and of physiological responses of neurons in the primate visual system.

Stone, L. S.↗
NASA NTRS1990

Research centrifuge accommodations on Space Station Freedom

Life sciences research using plants and animals on the Space Station Freedom requires the ability to maintain live subjects in a safe and low stress environment for long durations at microgravity and at one g. The need for a centrifuge to achieve these accelerations is evident. Programmatic, technical, and cost considerations currently favor a 2.5 meter diameter centrifuge located either in the end cone of a Space Station Freedom node or in a separate module. A centrifuge facility could support a mix of rodent, plant, and small primate habitats. An automated cage extractor could be used to remove modular habitats in pairs without stopping the main rotor, minimizing the disruption to experiment protocols. The accommodation of such a centrifuge facility on the Space Station represents a significant demand on the crew time, power, data, volume, and logistics capability. It will contribute to a better understanding of the effects of space flight on humans, an understanding of plant growth in space for the eventual production of food, and an understanding of the role of gravity in biological processes.

Arno, Roger D.↗
NASA NTRS1991

Microgravity Experiments On Animals

Paper describes experiments on animal subjects planned for Spacelab Life Sciences 1 mission. Laboratory equipment evaluated, and physiological experiments performed. Represents first step in establishing technology for maintaining and manipulating rodents, nonhuman primates, amphibians, and plants during space flight without jeopardizing crew's environment. In addition, experiments focus on effects of microgravity on cardiopulmonary, cardiovascular, and musculoskeletal systems; on regulation of volume of blood and production of red blood cells; and on calcium metabolism and gravity receptors.

Dalton, B. P.↗
NASA NTRS1990

Centrifuge Facility Conceptual System Study. Volume 1: Facility overview and habitats

The results are presented for a NASA Phase 1 study conducted from mid 1987 through mid 1989 at Ames Research Center. The Centrifuge Facility is the major element of the biological research facility for the implementation of NASA's Life Science Research Program on Space Station Freedom using non-human specimens (such as small primates, rodents, plants, insects, cell tissues). Five systems are described which comprise the Facility: habitats, holding units, centrifuge, glovebox, and service unit. Volume 1 presents a facility overview and describes the habitats - modular units which house living specimens.

Synnestvedt, Robert↗
NASA NTRS1991

Centrifuge facility conceptual system study. Volume 2: Facility systems and study summary

The Centrifuge Facility is a major element of the biological research facility for the implementation of NASA's Life Science Research Program on Space Station Freedom using nonhuman species (small primates, rodents, plants, insects, cell tissues, etc.). The Centrifuge Facility consists of a variable gravity Centrifuge to provide artificial gravity up to 2 earth G's' a Holding System to maintain specimens at microgravity levels, a Glovebox, and a Service Unit for servicing specimen chambers. The following subject areas are covered: (1) Holding System; (2) Centrifuge System; (3) Glovebox System; (4) Service System; and (5) system study summary.

Synnestvedt, Robert↗
NASA NTRS1991

A non-invasive measure of minerals and electrolytes in tissue

A system for collecting epithelial cells from the oral mucosa for the determination of ion concentration is discussed with application to the study of man's adaptation to microgravity. A number of characteristics of these cells influenced the choice for clinical testing. They are non-cornified epithelial cells located on the inferior aspect of the tongue; therefore, they are well protected from trauma. They have the capability of reflecting relatively recent physiologic changes since they are renewed every three days and have aerobic metabolism. Most importantly, they are easily accessible and can be removed by a wooden applicator stick with minimum discomfort. Smears of cells removed in this manner show predominantly individual cells rather than sheets of contiuous cells. This facilitates the visual isolation of single cells with the electron microscope for analysis. NASA's principle effort in the development of a test to measure the ion concentration in sublingual cells has been research by the biomedical program carried out by scientists with expertise in skeletal metabolism. These efforts were directed toward determining the biological meaning and deviations in interacellular ions in nonhuman primates and in male volunteers for experiments in a model for weightlessness. A brief one page summary of the experiments and results are presented.

Arnaud, Sara B.↗
NASA NTRS1990

Processing of form stimuli presented unilaterally in humans, chimpanzees (Pan troglodytes), and monkeys (Macaca mulatta)

Visual forms were unilaterally presented using a video-task paradigm to ten humans, chimpanzees, and two rhesus monkeys to determine whether hemispheric advantages existed in the processing of these stimuli. Both accuracy and reaction time served as dependent measures. For the chimpanzees, a significant right hemisphere advantage was found within the first three test sessions. The humans and monkeys failed to show a hemispheric advantage as determined by accuracy scores. Analysis of reaction time data revealed a significant left hemisphere advantage for the monkeys. A visual half-field x block interaction was found for the chimpanzees, with a significant left visual field advantage in block two, whereas a right visual field advantage was found in block four. In the human subjects, a left visual field advantage was found in block three when they used their right hands to respond. The results are discussed in relation to recent reports of hemispheric advantages for nonhuman primates.

Hopkins, William D.↗
NASA NTRS1991

Man in space - The use of animal models

The use of animal surrogates as experimental subjects in order to provide essential missing information on the effects of long-term spaceflights, to validate countermeasures, and to test medical treatment techniques is discussed. Research needs also include the definition of biomedical adaptations to flight, and the developments of standards for safe space missions to assure human health and productivity during and following flight. NASA research plans in this area are outlined. Over the next 40 years, NASA plans to concentrate on the use of rodents and nonhuman primates as the models of choice for various physiological responses observed in humans during extended stays in space. This research will include flights on the Space Shuttle, unmanned biosatellites, and the Space Station Freedom.

Ballard, Rodney W.↗
NASA NTRS1990

International Union of Physiological Sciences Commission on Gravitational Physiology, Annual Meeting, 11th, Lyons, France, Sept. 25-27, 1989, Proceedings

Topics discussed include recent space flight results in gravitational physiology, cardiovascular changes, current concepts in gravitational physiology, musculoskeletal changes, gravity and the cardiovascular system, hypergravic conditions, and head-down tilt. Papers are presented on the effect of space flight on the ultrastructure of the rat cerebellar and hemisphere cortex, a comparative study of cardiovascular responses in primates exposed to tilt test and lower body positive pressure, catecholamines during short- and long-term head-down bedrest, and effects of a 40-day tail-suspension on rat weight-bearing bones. Attention is also given to otolith versus vertical semicircular canal input in the inhibition of horizontal postrotatory nystagmus, cardiovascular responses to sustained acceleration, effects of high sustained hypergravity on plasma catecholamines, and the carotid baroreceptor cardiac-vagal reflex responses during 10 days of head-down tilt.

Reynolds, Orr E.↗
NASA NTRS1991

A Variational Assimilation Method for Satellite and Conventional Data: Model 2 (version 1)

The Model II variational data assimilation model is the second of the four variational models designed to blend diverse meteorological data into a dynamically constrained data set. Model II differs from Model I in that it includes the thermodynamic equation as the fifth dynamical constraint. Thus, Model II includes all five of the primative equations that govern atmospheric flow for a dry atmosphere.

Achtemeier, Gary L.↗