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81.
The MAP/WINE winter 1983/84 is studied using the LF-MF-HF A3 absorption and 5 kHz atmospherics observed in Czechoslovakia and some other data. The “normal” winter anomaly in Central Europe is developed well in this winter (maximum in mid-January) and appears to be “free of geomagnetic contamination”. The stratospheric warming activity and related changes of prevailing zonal wind in the lower thermosphere in February and March 1984 are followed by decreases of absorption of radio waves. It agrees with our results from preceding winters /1/.  相似文献   
82.
Our purpose is the forecast of the global radiation. As a first step we try to determine the global radiation as function of other predictable parameters. First the daily average values of the relative global radiation was considered as parabolic function of the cloud coverage obtained from METEOSAT images, an empirical formula was determined for calculation of the relative global radiation from the cloud amount. The correct this formula the cloud coverage and ground based visibility data were used. The value of the multiple correlation coefficient presenting the accuracy of the new formula was 0.96 for Budapest, and 0.93 for region of Hungary. This fact indicates that we have a sufficiently correct formula for calculation of the global radiation.  相似文献   
83.
Abstract Microbial mats are self-sustained, functionally complex ecosystems that make good models for the understanding of past and present microbial ecosystems as well as putative extraterrestrial ecosystems. Ecological theory suggests that the composition of these communities might be affected by nutrient availability and disturbance frequency. We characterized two microbial mats from two contrasting environments in the oligotrophic Cuatro Ciénegas Basin: a permanent green pool and a red desiccation pond. We analyzed their taxonomic structure and composition by means of 16S rRNA clone libraries and metagenomics and inferred their metabolic role by the analysis of functional traits in the most abundant organisms. Both mats showed a high diversity with metabolically diverse members and strongly differed in structure and composition. The green mat had a higher species richness and evenness than the red mat, which was dominated by a lineage of Pseudomonas. Autotrophs were abundant in the green mat, and heterotrophs were abundant in the red mat. When comparing with other mats and stromatolites, we found that taxonomic composition was not shared at species level but at order level, which suggests environmental filtering for phylogenetically conserved functional traits with random selection of particular organisms. The highest diversity and composition similarity was observed among systems from stable environments, which suggests that disturbance regimes might affect diversity more strongly than nutrient availability, since oligotrophy does not appear to prevent the establishment of complex and diverse microbial mat communities. These results are discussed in light of the search for extraterrestrial life. Key Words: Cuatro Ciénegas-Metagenomics-Microbial mats-Oligotrophic-Phosphorus limitation-Stromatolites. Astrobiology 12, 659-673.  相似文献   
84.
Cryptoendolithic microbial communities and epilithic lichens have been considered as appropriate candidates for the scenario of lithopanspermia, which proposes a natural interplanetary exchange of organisms by means of rocks that have been impact ejected from their planet of origin. So far, the hardiness of these terrestrial organisms in the severe and hostile conditions of space has not been tested over extended periods of time. A first long-term (1.5 years) exposure experiment in space was performed with a variety of rock-colonizing eukaryotic organisms at the International Space Station on board the European EXPOSE-E facility. Organisms were selected that are especially adapted to cope with the environmental extremes of their natural habitats. It was found that some-but not all-of those most robust microbial communities from extremely hostile regions on Earth are also partially resistant to the even more hostile environment of outer space, including high vacuum, temperature fluctuation, the full spectrum of extraterrestrial solar electromagnetic radiation, and cosmic ionizing radiation. Although the reported experimental period of 1.5 years in space is not comparable with the time spans of thousands or millions of years believed to be required for lithopanspermia, our data provide first evidence of the differential hardiness of cryptoendolithic communities in space.  相似文献   
85.
Plávalová E 《Astrobiology》2012,12(4):361-369
When a star is described as a spectral class G2V, we know that the star is similar to our Sun. We know its approximate mass, temperature, age, and size. When working with an extrasolar planet database, it is very useful to have a taxonomy scale (classification) such as, for example, the Harvard classification for stars. The taxonomy has to be easily interpreted and present the most relevant information about extrasolar planets. I propose an extrasolar planet taxonomy scale with four parameters. The first parameter concerns the mass of an extrasolar planet in the form of units of the mass of other known planets, where M represents the mass of Mercury, E that of Earth, N Neptune, and J Jupiter. The second parameter is the planet's distance from its parent star (semimajor axis) described in a logarithm with base 10. The third parameter is the mean Dyson temperature of the extrasolar planet, for which I established four main temperature classes: F represents the Freezing class, W the Water class, G the Gaseous class, and R the Roasters class. I devised one additional class, however: P, the Pulsar class, which concerns extrasolar planets orbiting pulsar stars. The fourth parameter is eccentricity. If the attributes of the surface of the extrasolar planet are known, we are able to establish this additional parameter where t represents a terrestrial planet, g a gaseous planet, and i an ice planet. According to this taxonomy scale, for example, Earth is 1E0W0t, Neptune is 1N1.5F0i, and extrasolar planet 55 Cnc e is 9E-1.8R1.  相似文献   
86.
The design presented in this paper is in response to the revolution in private space activities, the increasing public interest in commercial flights to space and the utilization of structures such as space hotels or private orbital habitats. The baseline for the Omicron design concept is the Russian Salyut derived space station module. Salyut was the first space station to orbit the Earth. Its unique design and technical features were what made the development of space stations Salyut 1–7, MIR and the International Space Station (ISS) Zwezda service module possible. Due to its versatility and the reliable operating launch vehicle Proton, this space module series has the potential to be adapted for space hotel development. This paper proposes a conceptual design of the space habitat called Omicron, with particular focus on interior design for the microgravity environment. The Omicron concepts address the needs of space tourism with a strong emphasis on the safety and comfort of the spaceflight participants. The Omicron habitat supports three inhabitants in nominal conditions (e.g., two passengers and one astronaut). The habitat provides a flexible interior, facilities and spaces dynamically transforming in order to accommodate various types of activities, which will be performed in an organically formed interior supporting spatial orientation and movement in microgravity. The future development potential of Omicron is also considered. The baseline version is composed solely of one rigid module with an inverted cupola for observations. An alternative version offers more space using an inflatable structure. Finally, a combination of multiple Omicron modules enables the creation of a larger orbital habitat. The Omicron's subsystems support a few days visit by trained passengers. The transport to the habitat would be provided e.g., by the Soyuz TMA spacecraft carried by the Soyuz launch vehicle in the early stage of Omicron's development, before a fully reusable spacecraft would be available.  相似文献   
87.
In a large majority of lunar and planetary surface images, impact craters are the most abundant geological features. Therefore, it is not surprising that crater detection algorithms (CDAs) are one of the most studied subjects of image processing and analysis in lunar and planetary science. In this work we are proposing an Integrated CDA, consisting of: (1) utilization of DEM (digital elevation map)-based CDA; (2) utilization of an optical-based CDA; (3) re-projection of used datasets and crater coordinates from normal to rotated view and back; (4) correction of the brightness and contrast of a used optical image; and (5) tile generation for the optical-based CDA and an assembling of results with an elimination of multiple detections, in combination with a pyramid approach down to the resolution of the available DEM image; and (6) a final integration of the results of DEM-based and optical-based CDAs, including a removal of duplicates. The proposed CDA is applied to one specific asteroid-like body, the small Martian moon Phobos. The experimental evaluation of the proposed CDA is done by a manual verification of crater-candidates and a search for uncatalogued craters. The evaluation has shown that the proposed CDA was used successfully for cataloging Phobos craters. The major result of this paper is the PH9224GT – currently the most complete global catalogue of the 9224 Phobos craters. The possible applications of the new catalogue are: (1) age estimations for any selected location; and (2) comparison/evaluation of the different chronology and production functions for Phobos. This confirms the practical applicability of the new Integrated CDA – an additional result of this paper, which can be used in order to considerably extend the current crater catalogues.  相似文献   
88.
89.
Book reviews     
The general significance of streamers of the solar corona is discussed in the frame of our knowledge of the solar wind phenomenon and the large-scale solar magnetic structure. Thermodynamical and geometric parameters of streamers observed and measured at total solar eclipses are reviewed. Both the low part (in the form of a helmet with a cusp) and the external part (in the form of a stalk extended at many solar radii) are considered. The modelling of streamers starts with the analysis of effects produced by the solar wind flow on a magnetic structure. Facts and arguments are presented in favor of a model with a current sheet and reconnection processes going on along the axis of the streamer, especially in the non-collisional part of the radially extended streamer. Further development of the Pneuman and Kopp (1971) model is discussed, including difficulties occurring in the interpretation of a stationary solution. An empirical model satisfying observations is presented. Future researchs on streamers were discussed with emphasis on observations to be done with the space-borne coronagraphs on the SOHO spacecraft.  相似文献   
90.
Although there is no direct evidence yet for the existence of life on Mars, it is reasonable to conclude that the emergence of life on Earth, which appears to have been controlled by universal laws of physics and chemistry, may have been repeated elsewhere in the universe. The dual approach of synthesis and analysis in our experimental studies has provided ample evidence in support of this hypothesis.  相似文献   
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