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At least 109 records · Page 6
All sourcesNASA NTRSDOE OSTI
NASA NTRS1990

The earliest fossil evidence for sexual dimorphism in primates

Recently obtained material of the early Eocene primate Notharctus venticolus, including two partial skulls from a single stratigraphic horizon, provides the geologically earliest evidence of sexual dimorphism in canine size and shape in primates and the only unequivocal evidence for such dimorphism in strepsirhines. By analogy with living platyrrhines, these data suggest that Notharctus venticolus may have lived in polygynous social groups characterized by a relatively high level of intermale competition for mates and other limited resources. The anatomy of the upper incisors and related evidence imply that Notharctus is not as closely related to extant lemuriform primates as has been recently proposed. The early Eocene evidence for canine sexual dimorphism reported here, and its occurrence in a nonanthropoid, indicates that in the order Primates such a condition is either primitive or evolved independently more than once.

Krishtalka, Leonard↗
NASA NTRS1991

International disaster research

No existing telecommunications system can be expected to provide strategy and tactics appropriate to the complex, many faceted problem of disaster. Despite the exciting capabilities of space, communications, remote sensing, and the miracles of modern medicine, complete turnkey transfers to the disaster problem do not make the fit, and cannot be expected to do so. In 1980, a Presidential team assigned the mission of exploring disaster response within the U.S. Federal Government encountered an unanticipated obstacle: disaster was essentially undefined. In the absence of a scientifically based paradigm of disaster, there can be no measure of cost effectiveness, optimum design of manpower structure, or precise application of any technology. These problems spawned a 10-year, multidisciplinary study designed to define the origins, anatomy, and necessary management techniques for catastrophes. The design of the study necessarily reflects interests and expertise in disaster medicine, emergency medicine, telecommunications, computer communications, and forencsic sciences. This study is described.

Silverstein, Martin Elliot↗
NASA NTRS1994

Surgery applications of virtual reality

Virtual reality is a computer-generated technology which allows information to be displayed in a simulated, bus lifelike, environment. In this simulated 'world', users can move and interact as if they were actually a part of that world. This new technology will be useful in many different fields, including the field of surgery. Virtual reality systems can be used to teach surgical anatomy, diagnose surgical problems, plan operations, simulate and perform surgical procedures (telesurgery), and predict the outcomes of surgery. The authors of this paper describe the basic components of a virtual reality surgical system. These components include: the virtual world, the virtual tools, the anatomical model, the software platform, the host computer, the interface, and the head-coupled display. In the chapter they also review the progress towards using virtual reality for surgical training, planning, telesurgery, and predicting outcomes. Finally, the authors present a training system being developed for the practice of new procedures in abdominal surgery.

Rosen, Joseph↗
NASA NTRS1993

Development and evaluation of a musculoskeletal model of the elbow joint complex

This paper describes the development and evaluation of a musculoskeletal model that represents human elbow flexion-extension and forearm pronation-supination. The length, velocity, and moment arm for each of the eight musculotendon actuators were based on skeletal anatomy and position. Musculotendon parameters were determined for each actuator and verified by comparing analytical torque-angle curves with experimental joint torque data. The parameters and skeletal geometry were also utilized in the musculoskeletal model for the analysis of ballistic elbow joint complex movements. The key objective was to develop a computational model, guided by parameterized optimal control, to investigate the relationship among patterns of muscle excitation, individual muscle forces, and movement kinematics. The model was verified using experimental kinematic, torque, and electromyographic data from volunteer subjects performing ballistic elbow joint complex movements.

Gonzalez, Roger V.↗
NASA NTRS1994

From Undersea to Outer Space: The STS-40 Jellyfish Experiment

This is an educational production featuring 'Ari', animated jellyfish who recounts his journey into space. Jellyfish were flown aboard the shuttle to study the effects of microgravity on living organisms. Topics Ari explores are: microgravity, life sciences, similarities between jellyfish and humans, and the life cycle and anatomy of a jellyfish.

Source record↗
NASA NTRS1991

A decade of telerobotics in rehabilitation: Demonstrated utility blocked by the high cost of manipulation and the complexity of the user interface

The Stanford/VA Interactive Robotics Laboratory set out in 1978 to test the hypothesis that industrial robotics technology could be applied to serve the manipulation needs of severely impaired individuals. Five generations of hardware, three generations of system software, and over 125 experimental subjects later, we believe that genuine utility is achievable. The experience includes development of over 65 task applications using voiced command, joystick control, natural language command and 3D object designation technology. A brief foray into virtual environments, using flight simulator technology, was instructive. If reality and virtuality come for comparable prices, you cannot beat reality. A detailed review of assistive robot anatomy and the performance specifications needed to achieve cost/beneficial utility will be used to support discussion of the future of rehabilitation telerobotics. Poised on the threshold of commercial viability, but constrained by the high cost of technically adequate manipulators, this worthy application domain flounders temporarily. In the long run, it will be the user interface that governs utility.

Leifer, Larry↗
NASA NTRS1993

Transesophageal echocardiographic evaluation of baboons during microgravity induced by parabolic flight

Transthoracic echocardiography (TTE) is a feasible method to noninvasively examine cardiac anatomy during parabolic flight. However, transducer placement on the chest wall is very difficult to maintain during transition to microgravity. In addition, TTE requires the use of low frequency transponders which limit resolution. Transesophical echocardiography (TEE) is an established imaging technique which obtains echocardiographic information from the esophagus. It is a safe procedure and provides higher quality images of cardiac structure than obtained with TTE. This study is designed to determine whether TEE was feasible to perform during parabolic flight and to determine whether acute central volume responses occur in acute transition to zero gravity by direct visualization of the cardiac chambers.

Vernalis, Marina N.↗
NASA NTRS1994

Nematode radiobiology and development in space. Results from IML-1

The Radiat experiment was one of 17 investigations which used the ESA Biorack on IML-1 (International Microgravity Laboratory) and it had two objectives. The first objective was to isolate and characterize mutations induced by cosmic rays; the second was to assess the fidelity of development in 0-gravity over two consecutive generations. Two strategies were used to isolate mutations in a set of essential genes or a specific gene and to correlate the genetic events with the passage of charged particles. The results were isolation of 60 lethal mutations whose phenotypes are related to the local pattern of energy deposition. 12 mutations in the unc-22 gene include large deletions as characterized by DNA hybridization studies. Development of nematodes proceeded through two consecutive generations with no obvious defects. Cytoplasmic determinants in embryos, nuclear location and symmetry of cellular anatomy were normal as were Mendelian segregation and recombination of genetic markers.

Nelson, Gregory A.↗
NASA NTRS1995

Genetic and molecular dosimetry of HZE radiation (US-1 RADIAT)

In order to estimate radiation exposure in space, experiments were conducted during the 1st International Microgravity Laboratory (IML-1) mission in order to isolate genetic changes in animal cells caused by cosmic rays. The space measurements were evaluated against results from synthetic cosmic rays produced by particle accelerators on the ground. The biological material used was the tiny soil nematode, Caenorhabditis elegans. The measurements were made by thermoluminescent detectors and plastic nuclear track detectors. The development and the chromosome mechanics in microgravity were studied, and the mutagenesis induced by radiation exposure was analyzed. The results showed that there are no obvious differences in the development, behavior and chromosome mechanics, as a function of gravity unloading (reproduction, self-fertilization and mating of males with hermaphrodites, gross anatomy, symmetry and gametogenesis, pairing, disjoining and recombination of chromosomes). A variety of mutants were isolated, and it was noted that mutants isolated from regions of identified high particles were more severely affected than those isolated by random screening. Linear energy transfer particles seem to favor large scale genetic lesions.

Nelson, Gregory A.↗
NASA NTRS1995

Applied virtual reality in aerospace design

A virtual reality (VR) applications program has been under development at the Marshall Space Flight Center (MSFC) since 1989. The objectives of the MSFC VR Applications Program are to develop, assess, validate, and utilize VR in hardware development, operations development and support, mission operations training and science training. Before VR can be used with confidence in a particular application, VR must be validated for that class of applications. For that reason, specific validation studies for selected classes of applications have been proposed and are currently underway. These include macro-ergonomic 'control room class' design analysis, Spacelab stowage reconfiguration training, a full-body microgravity functional reach simulator, a gross anatomy teaching simulator, and micro-ergonomic design analysis. This paper describes the MSFC VR Applications Program and the validation studies.

Hale, Joseph P.↗
NASA NTRS1994

Effects of radiation quality, intensity, and duration on photosynthesis and growth

Differences in radiation quality from the six most common electric lamps have little effect on photosynthetic rate. Radiation quality primarily alters growth because of changes in branching or internode elongation, which change radiation absorption. Growth and yield in wheat appear to be insensitive to radiation quality. Growth and yield in soybeans can be slightly increased under high pressure sodium (HPS) lamps compared to metal halide lamps, in spite of greatly reduced chlorophyll concentrations under HPS lamps. Daily integrated photosynthetic photon flux (mol m(exp -2)d(exp -1)) most directly determines leaf anatomy and growth. Photosynthetic photon flux (PPF) levels of 800 (mu)mol m(exp -2)s(exp -1) are adequate to simulate field daily-integrated PPF levels for both short and long day plants, but plant canopies can benefit from much higher PPF levels.

Bugbee, Bruce↗
NASA NTRS1995

Applied Virtual Reality Research and Applications at NASA/Marshall Space Flight Center

A Virtual Reality (VR) applications program has been under development at NASA/Marshall Space Flight Center (MSFC) since 1989. The objectives of the MSFC VR Applications Program are to develop, assess, validate, and utilize VR in hardware development, operations development and support, mission operations training and science training. Before this technology can be utilized with confidence in these applications, it must be validated for each particular class of application. That is, the precision and reliability with which it maps onto real settings and scenarios, representative of a class, must be calculated and assessed. The approach of the MSFC VR Applications Program is to develop and validate appropriate virtual environments and associated object kinematic and behavior attributes for specific classes of applications. These application-specific environments and associated simulations will be validated, where possible, through empirical comparisons with existing, accepted tools and methodologies. These validated VR analytical tools will then be available for use in the design and development of space systems and operations and in training and mission support systems. Specific validation studies for selected classes of applications have been completed or are currently underway. These include macro-ergonomic "control-room class" design analysis, Spacelab stowage reconfiguration training, a full-body micro-gravity functional reach simulator, and a gross anatomy teaching simulator. This paper describes the MSFC VR Applications Program and the validation studies.

Hale, Joseph P.↗
NASA NTRS1997

Effects of Spaceflight on Drosophila Neural Development

The major goal from the animal side, however, has been achieved, namely to develop Drosophila lines where we can assay individual neuromuscular endings directly without dissection. This was achieved by means of using the GAL4-UAS system, where we have succeeded in establishing stocks of flies where the key neuromuscular connections can be assayed directly in undissected larvae by means of the expression of endogenously fluorescent reporters in the specific motor endings. The green fluorescent protein (GFP) as a reporter allows scoring of neural anatomy en-masse in whole mount using fluorescent microscopy without the need for either dissection or specific labeling. Two stocks have been developed. The first, which we developed first, uses the S65T mutant form, which has a dramatically brighter expression than the native protein. This animal will use GAL4 drivers with expression under the control of the elav gene, and which will ensure expression in all neurons of the embryo and larva. The second transgenic animal we have developed is of a novel kind, and makes use of dicistronic design, so that two copies of the protein will be expressed per insert. We have also developed a tricistronic form, but this has not yet been transformed into flies, and we do not imagine that this third line will be ready in time for the flight.

Keshishian, Haig S.↗
NASA NTRS1992

Structural Development of the Oat Plant

The anatomical structure and morphology of the oat plant (Avena sativa L.) have been reviewed previously by Hector (1936), Bonnett (1961a,b) and Coffman (1977). In addition, Bonnett published detailed accounts of oat panicle development (1937, 1961a,b). This work has been summarized by Esau in her book, Anatomy of Seed Plants, in 1977. It is not the purpose of the present authors to simply go over all this same material again in a repetitive fashion, but rather, to emphasize some of the more recent and previously overlooked work on structural development of the oat plant, with emphasis on the major cultivated species, A. sativa (see Stanton, 1955; Coffman, 1977 for descriptions of this species). The material presented here should be of use to oat breeders, agronomists, and plant physiologists.

Kaufman, Peter B.↗
NASA NTRS1997

Force Model for Control of Tendon Driven Hands

Knowing the tendon forces generated for a given task such as grasping via a model, an artificial hand can be controlled. A two-dimensional force model for the index finger was developed. This system is assumed to be in static equilibrium, therefore, the equations of equilibrium were applied at each joint. Constraint equations describing the tendon branch connectivity were used. Gaussian elimination was used to solve for the unknowns of the Linear system. Results from initial work on estimating tendon forces in post-operative hands during active motion therapy were discussed. The results are important for understanding the effects of hand position on tendon tension, elastic effects on tendon tension, and overall functional anatomy of the hand.

Pena, Edward↗
NASA NTRS1994

The Influence of Gravito-Inertial Force on Sensorimotor Integration and Reflexive Responses

Sensorimotor responses (e.g.. eye movements, spinal reflexes, etc depend upon the interpretation of the neural signals from the sensory systems. Since neural signals from the otoliths may represent either tilt (gravity) or translation (linear inertial force), sensory signals from the otolith organs are necessarily somewhat ambiguous. Therefore. the neural responses to changing otolith signals depend upon the context of the stimulation (e.g- active vs. passive, relative orientation of gravity, etc.) as well as upon other sensory signals (e.g., vision. canals, etc.). This session will focus upon the -role -played by the sensory signals from the otolith organs in producing efficient sensorimotor and behavioral responses. Curthoys will show the influence of the peripheral anatomy and physiology. Tomko will discuss the influence of tilt and translational otolith signals on eye movements. Merfeld will demonstrate the rate otolith organs play during the interaction of sensory signals from the canals and otoliths. Watt will show the influence of the otoliths on spinal/postural responses. Guedry will discuss the contribution of vestibular information to "path of movement"' perception and to the development of a stable vertical reference. Sensorimotor responses to the ambiguous inertial force stimulation provide an important tool to investigate how the nervous system processes patterns of sensory information and yields functional sensorimotor responses.

Curthoys, Ian S.↗
NASA NTRS1994

Gravity and the Adaptation of Form and Function in Lower Vertebrates

Comparative data emphasizing lower vertebrates will be used to justify the following generalized conclusions or expectations: 1) Gravitational stress produces adaptive increases in arterial pressure. 2) Gravitational stress produces adaptive reorganization of anatomy. 3) Natural selection favors small body size in high G-stress environments. 4) Gravitational stress produces low-compliant perivascular tissues (morphological antigravity suit). 5) Gradients or regional zonation of vascular characters evolve along the length of elongate vertebrates living in high G-stress environments. Presentation of information will include new data gathered by the author and Dr. Alan Hargens while the author was a NRC Senior Research Associate at NASA Ames Research Center. While there is no published abstract provided at the meeting, a symposium manuscript will be published in a special volume of Journal of Experimental Zoology.

Lillywhite, Harvey B.↗
NASA NTRS2001

Association of American Geographers, Remote Sensing Specialty Group Special Issue of Geocarto International

This special issue continues the precedence of the Association of American Geographers (AAG), Remote Sensing Specialty Group (RSSG) for publishing selected articles in Geocarto International as a by-product from the AAG annual meeting. As editors, we issued earlier this year, a solicitation for papers to be published in a special issue of Geocarto International that were presented in RSSG-sponsored sessions at the 2001 AAG annual meeting held in New York City on February 27-March 3. Although not an absolute requisite for publication, the vast majority of the papers in this special issue were presented at this year's AAG meeting in New York. Other articles in this issue that were not part of a paper or poster session at the 2001 AAG meeting are authored by RSSG members. Under the auspices of the RSSG, this special Geocarto International issue provides even more compelling evidence of the inextricable linkage between remote sensing and geography. The papers in this special issue fall into four general themes: 1) Urban Analysis and Techniques for Urban Analysis; 2) Land Use/Land Cover Analysis; 3) Fire Modeling Assessment; and 4) Techniques. The first four papers herein are concerned with the use of remote sensing for analysis of urban areas, and with use or development of techniques to better characterize urban areas using remote sensing data. As the lead paper in this grouping, Rashed et al., examine the usage of spectral mixture analysis (SMA) for analyzing satellite imagery of urban areas as opposed to more 'standard' methods of classification. Here SMA has been applied to IRS-1C satellite multispectral imagery to extract measures that better describe the 'anatomy' of the greater Cairo, Egypt region. Following this paper, Weng and Lo describe how Landsat TM data have been used to monitor land cover types and to estimate biomass parameters within an urban environment. The research reported in this paper applies an integrated GIS (Geographic Information System) approach for detecting urban growth and assessing its impact on biomass in the Zhujiang Delta, China. The remaining two papers in this first grouping deal with improved techniques for characterizing and analyzing urban areas using remote sensing data. Myint examines the use of texture analysis to better classify urban features. Here wavelet analysis has been employed to assist in deriving a more robust classification of the urban environment from high spatial resolution, multispectral aircraft data. Mesev provides insight on how through the modification of the standard maximum likelihood image analysis technique, population census data can be used enhance the overall robustness of urban image classification through the modification of the standard maximum likelihood image analysis technique.

Allen, Thomas R.↗