23,705 research outputs found
An assessment of ground-based techniques for detecting other planetary systems. Volume 1: An overview
The feasibility and limitations of ground-based techniques for detecting other planetary systems are discussed as well as the level of accuracy at which these limitations would occur and the extent to which they can be overcome by new technology and instrumenation. Workshop conclusions and recommendations are summarized and a proposed high priority program is considered
Integrated Expert Management Knowledge on OSI Network Management Objects
The management of modern telecommunications networks must satisfy
ever-increasing operational demands. We propose a study for the improvement
of intelligent administration techniques in telecommunications networks.
This task is achieved by integrating knowledge base of expert system within the
management information used to manage a network. For this purpose, an extension
of OSI management framework specifications language has been added
and investigated. For this goal, we shall use the language Guidelines for the
Definition of Managed Objects (GDMO) and a new property named RULE
which gathers important aspects of the facts and the knowledge base of the embedded
expert system. Networks can be managed easily by using this proposed
integration
Possible Observational Criteria for Distinguishing Brown Dwarfs from Planets
The difference in formation process between binary stars and planetary
systems is reflected in their composition as well as their orbital
architecture, particularly orbital eccentricity as a function of orbital
period. It is suggested here that this difference can be used as an
observational criterion to distinguish between brown dwarfs and planets.
Application of the orbital criterion suggests that with three possible
exceptions, all of the recently-discovered substellar companions discovered to
date may be brown dwarfs and not planets. These criterion may be used as a
guide for interpretation of the nature of sub-stellar mass companions to stars
in the future.Comment: LaTeX, 11 pages including 2 figures, accepted for publication in the
Astrophysical Journal Letter
Float-polishing process and analysis of float-polished quartz
A fluid-mechanical model is developed for the float-polishing process. In this model laminar flow between the sample and the lap results in pressure gradients at the grooves that support the sample on a fluid layer. The laminar fluid motion also produces supersmooth, damage-free surfaces. Quartz substrates for applications in high-stress environments were float polished, and their surfaces were analyzed by optical scatterometry, photoacoustic spectroscopy, and atomic force microscopy. The removal of 100 µm of material by a lapping-polishing process, with final float polishing, left low levels of subsurface damage, with a surface roughness of approximately 0.2-nm rms
Identification of two genes specifying folylpolyglutamate synthases
Genes specifying folylpolyglutamate synthase
An Assessment of Ground-Based Techniques for Detecting Other Planetary Systems. Volume 2: Position papers
The capabilities of several astronomical interferomenter system concepts are assessed and the effects of the Earth's atmosphere on astrometric precision are examined in detail. Included is an examination of the use of small aperture interferometry to detect planets in binary star systems. It is estimated that, for differential astrometric observation, an amplitude interferometer having two separate telescopes should permit observations of stars as faint as 14th magnitude and a positional accuracy of 0.00005 arc-sec. Instrumental, atmospheric, and photon noise errors that apply to interferometric observation are examined. It is suggested that the effects of atmospheric turbulence may be eliminated with the use of two color refractometer systems. Several sites for future telescopes dedicated to the search for planetary systems are identified
The synthesis of polyglutamate forms of folate by N. crassa
Synthesis of polyglutamate forms of folat
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