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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 595 records · Page 33
All sourcesNASA NTRSDOE OSTI
NASA NTRS1973

Visual field defects after missile injuries to the geniculo-striate pathway in man.

The main objective of the survey reported was a quantitative comparison of different visual functions at identical retinal points of individual patients. The possibility to develop objective forms of visual-field testing was also explored, taking into account reports by Frydrychowicz and Harms (1940) and Harms (1951). These investigators had insisted that pupillary responses to light are depressed in areas of homonymous scotomata. The shapes of homonymous visual field defects are discussed together with questions regarding the association and dissociation of symptoms.

Koerner, F.↗
NASA NTRS1970

An analysis of the circuitry of the visual pathway of the lateral eye of limullus

The methodology is discussed for three-dimensional analysis of the nervous system on the basis of electron micrographs of serial sections. An analysis is presented of a part of the circuitry of the rabbit retina. In addition, some exploratory work is reported with respect to the visual cortex of the cat brain. A proper technique for preservation of the visual cortex was worked out and a technique to localize microelectrode tips in the tissue in connection with electron microscopy was partially worked out.

Sjoestrand, F. S.↗
NASA NTRS1981

Phylogenetic sequence of metabolic pathways in Precambrian cellular life

A sequence of major metabolic events is presented as they may have appeared during prokaryote evolution. This is based on (1) the phylogenetic schema derived from sequences of bacterial ferredoxin, 2Fe-2S ferredoxin, 5S ribosomal RNA, and c-type cytochromes; (2) metabolic settings in which these macromolecules are found; and (3) metabolic capabilities of the prokaryotes that carry these molecules.

Barnabas, J.↗
NASA NTRS1982

Prebiotic organic matter - Possible pathways for synthesis in a geological context

Models for the accretion of the earth, core formation, differentiation of the planet into core, mantle, crust, and atmosphere, and prebiotic synthesis of organic materials are reviewed. The development of the Haldane-Oparin and Urey models is traced, and the effect of accretion time on the outgassing process and the composition of the consequent atmosphere is examined. Model prebiotic atmospheres are calculated, the extent of equilibration of the primitive atmosphere is studied and the evolution of the atmosphere prior to organic chemical evolution is reviewed. Finally, experimental progress in synthesis of biological monomers and polymers under presumed early earth conditions is covered.

Chang, S.↗
NASA NTRS1983

Pathways of evolution for man and machine

A simplified model of the future is introduced in order to examine the relations between man, machine, and extraterrestrial intelligence. The observed lack of extraterrestrials on earth is used as a boundary condition for the model. Two exobiological conclusions are obtained: (1) advanced extraterrestrials exist but are difficult to observe or to distinguish from natural phenomena, (2) lower level, man-like extraterrestrials, which are potentially observable, are rare in the Universe because they are rapidly replaced in the evolutinary sequence by the intelligent machines which they create. The decline of man is inferred and may take place as soon as 100 years from now or as long as 100,000 years from the present time. Thus, we are a short-lived species, having a life expectancy of only a million years. A note is appended on the rationale and methods of the search for extraterrestrial intelligence in light of the above calculations. The Tau Ceti and Epsilon Eridani systems present favourable opportunities for a radio-search experiment in 1987 and 1988, respectively.

Mclaughlin, W. I.↗
NASA NTRS1988

Fundamental kinetics and mechanistic pathways for oxidation reactions in supercritical water

Oxidation of the products of human metabolism in supercritical water has been shown to be an efficient way to accomplish the on-board water/waste recycling in future long-term space flights. Studies of the oxidation kinetics of methane to carbon dioxide in supercritical water are presented in this paper in order to enhance the fundamental understanding of the oxidation of human waste compounds in supercritical water. It is concluded that, although the elementary reaction models remain the best hope for simulating oxidation in supercritical water, several modifications to existing mechanisms need to be made to account for the role of water in the reaction mechanism.

Webley, Paul A.↗
NASA NTRS1989

Building a pathway to the planets - Expanding the frontiers of human exploration

The basic mission options, transportation, robotic precursors, technology, and human factors involved in the advance into interplanetary exploration and establishment of bases on the moon, planets, and planetary satellites are discussed. Case studies that have been undertaken for four candidate missions are briefly addressed. The role of international cooperation and the selection criteria pertaining to such missions are addressed.

O'Handley, Douglas A.↗
NASA NTRS1989

Human pathway to the solar system in the 21st century

Some proposed space exploration missions are examined. Consideration is given to requirements for human expeditions to Phobos and Mars and for establishing a lunar observatory and a permanent, self-sufficient facility on Mars. Earth-to-orbit transportation, propellant management, extraterrestrial construction and operations, life support technology, space transfer systems, and automation and robotics are examined in terms of proposed missions.

O'Handley, Douglas A.↗