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51.
In 1983 the NSIA sponsored the first Integrated Diagnostics National Conference. The major finding from this Conference was the lack of integration of those technologies which are part of the diagnostic process. Since that time, much has been done to implement the concept of integrated diagnostics. The NSIA has produced a baseline report on the implementation of the concept. This was followed by a series of Service programs aimed at implementation. The Office of the Secretary of Defense considers solutions to the diagnostic problem to be one of its major R&D goals. This paper discusses the progress made during the last three years on the implementation of integrated diagnostics. The paper also discusses the author's ideas on where the program is going.  相似文献   
52.
The emergence of private space actors may soon enable the growth of the novel market segments of space research and exploration, space resources utilization, and human access to space. The interdisciplinary field of Planetary Protection has to keep up with these advances. Planetary Protection is defined as a set of guidelines that aim to prevent the forward contamination of celestial bodies with biological material from Earth and the backward contamination of the terrestrial biosphere with extraterrestrial biological material. As space entrepreneurs acquire and develop the resources and competencies for commercial access to space, significant questions are expected to be raised in the future with respect to potential forward and backward contamination issues, particularly with respect to activities between Earth and Mars. Although such private activities do not seem to pose a serious Planetary Protection threat at the moment, certain preparatory steps need to be taken in order to prudently inform the relevant policy-making procedures. This work describes the application of the Contingent Valuation Method, a useful tool of the environmental economics discipline, with the aim of demonstrating a novel approach to estimate the economic valuation of the external benefits of preventing forward and backward contamination between Earth and Mars. Particularly, via a survey specifically developed for this purpose, a set of questions are used to elicit the perceived economic value that respondents place on the prevention of forward and backward contamination; the survey is administered to a national probability sample in Greece, and the generated data is processed through statistical analysis. The Contingent Valuation Method is a popular and well-established stated preference valuation technique; these techniques are often the more suitable choice for ex-ante valuations of future changes, and are currently the only known approach to capture all the aspects of the economic value of non-market goods. Through an initial proof-of-concept in Greece, the goal of this work is to provide useful insights on the expected external benefits of a national Planetary Protection policy to regulate future private space activities between Earth and Mars, and to encourage a larger-scale application of this tool in other countries around the world.  相似文献   
53.
In large systems using microwave amplifier arrays, the size, weight, and cost of individual energy sources require consideration of the use of a common power supply and energy storage bank. Complex energy control techniques may be necessary to protect the RF amplifier and to provide isolation of the faulted amplifier from the common energy source. Four approaches are discussed. Three of these are dependent on either the development of reliable arc-free microwave amplifiers or special isolator tubes, gas or vacuum types. A practical circuit using available components is suggested. Its advantages and limitations are discussed. Calculations are presented showing this approach can result in increased system efficiency, improved regulation, and large decreases in the size of the secondary capacitance bank for each microwave amplifier.  相似文献   
54.
Evolution and composition of baryonic matter is influenced by the evolution of other forms of matter and energy in the universe. At the time of primordial nucleosynthesis the universal expansion and thus the decrease of the density and temperature of baryonic matter were controlled by leptons and photons. Non-baryonic dark matter initiated the formation of clusters and galaxies, and to this day, dark matter largely determines the dynamics and geometries of these baryonic structures and indirectly influences their chemical evolution. Chemical analyses and isotopic abundance measurements in the solar system established the composition in the protosolar cloud (PSC). The abundances of nuclear species in the PSC led to the discovery of the magic numbers and the nuclear shell model, and they allowed the identification of nucleosynthetic sites and processes. To this day, we know the abundances of the ∼300 stable and long-lived nuclides infinitely better in the PSC than in any other sample of matter in the universe. Thus, we know the exact composition of a Galactic sample of intermediate age, allowing us to check on theories of Galactic evolution before and after the formation of the solar system. This paper specifically discusses the nucleosynthesis in the early universe and the Galactic evolution during the last 5 Gyr.  相似文献   
55.
We examined the use of hand gestures while people solved spatial reasoning problem in which they had to infer motion from static diagrams (mental animation problems). In Experiment 1, participants were asked to think aloud while solving mental animation problems. They gestured on more than 90% of problems, and most gestures expressed information about the component motions that was not stated in words. Two further experiments examined whether the gestures functioned in the mechanical inference process, or whether they merely served functions of expressing or communicating the results of this process. In these experiments, we examined the effects of instructions to think aloud, restricting participants' hand motions, and secondary tasks on mental animation performance. Although participants who were instructed to think aloud gestured more than control groups, some gestures occurred even in control conditions. A concurrent spatial tapping task impaired performance on mechanical reasoning, whereas a simple tapping task and restricting hand motions did not. These results indicate that gestures are a natural way of expressing the results of mental animation processes and suggest that spatial working memory and premotor representations are involved in mental animation. They provide no direct evidence that gestures are functional in the thought process itself, but do not rule out a role for overt gestures in this type of spatial thinking.  相似文献   
56.
This study determines through digital simulations the effects of two-antenna interference, defined as interference occurring at the ground guidance system antenna between the signals from two antennas located on, opposite sides of a space vehicle. It is demonstrated that errors due to interference during early booster flight are recovered from at booster cutoff; interference produced errors occurring shortly before cutoff are not recovered; and modulating the gain of one spaceborne antenna is beneficial to guidance in the interference region.  相似文献   
57.
Current and planned developments in the field of civilian and commercial2 satellite imagery promise a major expansion in international accessibility to remote sensing data and technologies. This paper addresses the implications of the expanding global access to land remote sensing data and their derived products. While atmospheric, meteorological, and oceanographic data is also widely available at cost or free of charge, it is land remote sensing – specifically the unique systems with high-resolution and frequent revisit times – that are of primary concern for international and regional security issues. Military and intelligence satellites are not addressed in this discussion of expansion due to their inherently controlled access, unless such systems also provide commercially available imagery or products (as is the case with some Russian systems).  相似文献   
58.
Ultraviolet light is present in the solar system and can cause major biological effects. The potential cytotoxic, mutagenic, and carcinogenic effects of UV have been studied at cellular and molecular level. Using cultured mouse embryonic fibroblasts (C3H10T1/2), we investigated the induction of mutation and transformation by UV and/or X-rays. Studies were also done with normal human mammary epithelial cells for cell inactivation and mutation induction. Curvlinear dose-response curves were observed for mutation and oncogenic transformation. The interaction between UV and X-rays depends on the sequence of exposure. When UV was given following X-irradiation, there was an additive effect. When UV was given prior to X-irradiation, however, there was a synergistic effect for both cell inactivation and transformation. The basic lesion(s) important for somatic mutation and transformation remains to be determined, and the fundamental mechanism(s) of UV and ionizing radiation interaction remains to be elucidated.  相似文献   
59.
The Orbiting Geophysical Observatories and the supporting ground checkout equipment, data acquisition and tracking stations and data processing equipment are designed to conduct large numbers of diverse experiments in space. Measurements will be made within the earth's atmosphere, ionosphere, exosphere, magnetosphere, and in cislunar space to obtain a better understanding of earth-sun relationships and of the earth as a planet. Configured to meet scientific requirements, the observatories include six booms to support detectors away from disturbances generated in the main body. Five degrees of freedom allow the orientation of experiments relative to three references — the earth, the sun, and the orbital plane. Power, thermal control, and data handling subsystems provide for the proper operation of the experiments and telemetry of the data. Ground stations receive these data, which are then processed into a form suitable for use by the experimenters. The systems have been designed to make available a standard spacecraft and support equipment which can be used repeatedly to carry large numbers of easily integrated experiments in a wide variety of orbits.  相似文献   
60.
Fox GE  Tran Q  Yonath A 《Astrobiology》2012,12(1):57-60
The emergence of an RNA entity capable of synthesizing peptides was a key prebiotic development. It is hypothesized that a precursor of the modern ribosomal exit tunnel was associated with this RNA entity (e.g., "protoribosome" or "bonding entity") from the earliest time and played an essential role. Various compounds that can bind and activate amino acids, including extremely short RNA chains carrying amino acids, and possibly di- or tripeptides, would have associated with the internal cavity of the protoribosome. This cavity hosts the site for peptide bond formation and adjacent to it a relatively elongated feature that could have evolved to the modern ribosomal exit tunnel, as it is wide enough to allow passage of an oligopeptide. When two of the compounds carrying amino acids or di- or tripeptides (to which we refer, for simplicity, as small aminoacylated RNAs) were in proximity within the heart of the protoribosome, a peptide bond could form spontaneously. The growing peptide would enter the nearby cavity and would not disrupt the attachment of the substrates to the protoribosome or interfere with the subsequent attachment of additional small aminoacylated RNAs. Additionally, the presence of the peptide in the cavity would increase the lifetime of the oligopeptide in the protoribosome. Thus, subsequent addition of another amino acid would be more likely than detachment from the protoribosome, and synthesis could continue. The early ability to synthesize peptides may have resulted in an abbreviated RNA World.  相似文献   
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