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201.
P Todd D M Klaus 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1996,17(6-7):3-10
A wide variety of observations on cells in space, admittedly made under constraining and unnatural conditions in many cases, have led to experimental results that were surprising or unexpected. Reproducibility, freedom from artifacts, and plausibility must be considered in all cases, even when results are not surprising. The papers in the symposium on "Theories and Models on the Biology of Cells in Space" are dedicated to the subject of the plausibility of cellular responses to gravity--inertial accelerations between 0 and 9.8 m/s2 and higher. The mechanical phenomena inside the cell, the gravitactic locomotion of single eukaryotic and prokaryotic cells, and the effects of inertial unloading on cellular physiology are addressed in theoretical and experimental studies. 相似文献
202.
Rapp D Naderi F Neugebauer M Sevilla D Sweetnam D Burnett D Wiens R Smith N Clark B McComas D Stansbery E 《Acta Astronautica》1996,39(1-4):229-238
The Suess-Urey (S-U) mission has been proposed as a NASA Discovery mission to return samples of matter from the Sun to the Earth for isotopic and chemical analyses in terrestrial laboratories to provide a major improvement in our knowledge of the average chemical and isotopic composition of the solar system. The S-U spacecraft and sample return capsule will be placed in a halo orbit around the L1 Sun-Earth libration point for two years to collect solar wind ions which implant into large passive collectors made of ultra-pure materials. Constant Spacecraft-Sun-Earth geometries enable simple spin stabilized attitude control, simple passive thermal control, and a fixed medium gain antenna. Low data requirements and the safety of a Sun-pointed spinner, result in extremely low mission operations costs. 相似文献
203.
The heating of solar coronal loops by the resonant absorption or phase-mixing of incident wave energy is investigated in the framework of 3D nonlinear magnetohydrodynamics (MHD) by means of numerical simulations. 相似文献
204.
I G Alekhina V G Mitrikas V M Petrov 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1994,14(10):409-414
The radiation risk at the end of the flight was calculated for the members of the main expeditions on the "Mir" station. It was based on the absorbed dose dynamics data measured by the board dosimeter. The radiation damage models created for standards of the radiation safety of the space flights were used in the calculations. The analysis of the obtained values of the risk and its dynamics for some cosmonauts are presented in the topic. The risk values delta P are close to the limited levels given by equation of delta P = 0.6 x 10 x T(-4), [this equation appears also as delta RHrad = 0.6 x 10(-4) x T later in the text] where T--is flight duration in months. 相似文献
205.
C S Layne B S Spooner 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1994,14(8):381-384
Changes in neuromuscular activation patterns associated with movements made in microgravity can contribute to muscular atrophy. Using EMG to monitor "postural" muscles, it was found that free floating arm flexions made in microgravity were not always preceded by neuromuscular activation patterns normally observed during movements made in unit gravity. Additionally, manipulation of foot sensory input during microgravity arm flexion impacted upon anticipatory postural muscle activation. 相似文献
206.
207.
We analyse the effects of semi-convection and overshooting on the predicted surface abundances after the first and second dredge-ups in 15 and 20 M Pop. I stars. Overshooting is applied either to the core boundary or to the boundaries of all convective zones. It is shown that the surface abundances are sensitive to the mixing scheme adopted in the interior. The models including semi-convection lead to lower12C/13C ratios than the other mixing schemes, while models with overshooting predict higher enhancements of sodium at the surface. 相似文献
208.
J. Smolinski J. L. Climenhaga Y. Huang Sh. Jiang M. Schmidt O. Stahl 《Space Science Reviews》1993,66(1-4):231-236
The profiles of H observed during the 1970–1992 period in the binary hypergiant HR 8752 (G0 Ia) are presented. We distinguish five typical H profiles designated as A, B, C, D and E types according to the number of emission and absorption features. The profiles of H are complex and contain several emission and absorption components, with: –130 km/s in emission or absorption, –84 km/s in absorption, –49 km/s in emission and about +6 km/s in emission. All of them are rather stable in radial velocities except of the main absorption component in the P Cygni profile with –84 km/s. The frequency of appearance and the periods of duration of the occurrence of the components is discussed. The duration times range between about 3 to 10 months for various components. The red emission component E2 is particularly interesting. Possible explanations of its origin are discussed.A long-term acceleration of the absorption component in the P Cygni profile is found; it can be interpreted as monotonous acceleration of the stellar wind. 相似文献
209.
210.
Effect of microgravity on Escherichia coli and MS-2 bacteriophage disinfection by iodinated resins 总被引:1,自引:0,他引:1
Experiments on chemical disinfection by iodinated resins were conducted on STS 50 (USML-1), which flew a 13 day mission during 1992. Fluid processing apparatus containing microorganisms and iodinated resins was assembled in either Manhattan, Kansas, or Boulder, Colorado, and loaded on-board the Space Shuttle for the mission. Pentaiodide resin was more effective than the triiodide resin against Escherichia coli. Both resins were more effective bactericides at unit gravity than microgravity because of cosedimentation of bacteria and iodinated resin beads. In bacteriophage experiments, the triiodide resin reduced the viable titer of MS-2 by nine logs. The few viable phage surviving chemical disinfection were associated with precipitant formation in the fluid processing apparatus. 相似文献