Ultrastructural and growth indices of Chlorella culture in multicomponent aquatic systems under space flight conditions.

Submicroscopic organization of Chlorella cells cultivated under space flight conditions in three-component aquatic system has been studied. Comparison of the experimental cells with that of the controls revealed certain rearrangements of cell organelles particularly, a reduction in the amount of reserve polysaccharides in chloroplasts, increase of cell vacuolization and mitochondrion volume, complication configuration of plasmalemma evaginations and invaginations, and also disturbances in the process of cytokinesis. More over an increase in the number of Chlorella cells infected by bacteria was shown in the experimental variant. No considerable differences were established in the growth characteristics of the experimental and control populations. A comparative cytological analysis revealed general regularities of organelles in Chlorella cells cultivated under space flight condition in the uni- and multicomponent systems.     

The Future of UAS: Standards, Regulations, and Operational Experiences [Workshop Report]

The outcomes of "the future of UAS: standards, regulations and operational experiences" workshop, held on the 7 -8 December 2006, in Brisbane, Queensland, Australia. The goal of the workshop was to identify recent international activities in the unmanned airborne systems (UAS) airspace integration problem. The workshop attracted a broad cross-section of the UAS community, including: airspace and safety regulators, developers, operators, and researchers. The three themes of discussion were: progress in the development of standards and regulations; lessons learnt from recent operations; and advances in new technologies. This summarises the activities of the workshop and explores the important outcomes and trends as perceived by these authors.     

High LET-induced H2AX phosphorylation around the Bragg curve.

We investigated the spatial distribution of the induction of the phosphorylated form of the histone protein H2AX (gamma-H2AX), known to be activated by DSBs. Following irradiation of human fibroblast cells with 600 MeV/nucleon silicon and 600 MeV/nucleon iron ions we observed the formation of gamma-H2AX aggregates in the shape of streaks stretching over several micrometers in an x/y plane. Polyethylene shielding was used to achieve a Bragg curve distribution with beam geometry parallel to the monolayer of cells. We present data that highlights the formation of immunofluorescent gamma-H2AX tracks showing the ion trajectories across the Bragg peak of irradiated human fibroblast cells. Qualitative analyses of these distributions indicated potentially increased clustering of DNA damage before the Bragg peak, enhanced gamma-H2AX distribution at the peak, and provided visual evidence of high-linear energy transfer particle traversal of cells beyond the Bragg peak in agreement with one-dimensional transport approximations. Spatial assessment of gamma-H2AX fluorescence may provide direct insights into DNA damage across the Bragg curve for high charge and energy ions including the biological consequences of shielding and possible contributors to bystander effects.     

A probabilistic assessment of cycle life of GTE disks made of granular materials

A technique of assessing cycle life and fracture probability for disks made of granular nickel alloys is presented. The technique makes it possible to take into account the probability of detecting inherent metallurgical anomalies available in disks. The calculation results are verified by experimental data.     

Capabilities of Kinematically Regular Satellite Systems with Symmetry Groups of the Second Type in the Problem of Continuous Single Coverage of the Earth

The problem of a continuous single coverage of the Earth by systems of satellites in circular orbits of equal radii is considered. The results of calculating the characteristics of kinematically regular systems consisting of 6 to 60 satellites and possessing symmetry groups of the second type are presented. It is shown that, when the number of satellites varies from 20 to 38 inclusive, the best systems of this class surpass all currently known systems with respect to their characteristics.__________Translated from Kosmicheskie Issledovaniya, Vol. 43, No. 3, 2005, pp. 215–223.Original Russian Text Copyright © 2005 by Mozhaev.     

Application of periodic solutions of three-dimensional three-body problem to designing the orbit of a space telescope

A method of constructing three-dimensional orbits with a necessary evolution in the system the Sun — (Earth + Moon) is described. The orbit (promising from the viewpoint of solving formulated research problems) of the Millimetron spacecraft is suggested. Feasibility of such an orbit is demonstrated, as well as a possibility to observe with its help the majority of objects on the celestial sphere and to transmit the data to the Earth.     

Elimination of relative secular drift of orbits of two satellites caused by polar oblateness of the Earth

A method of elimination of relative secular drifts in satellite formations is suggested for the case of influence of a perturbation due to polar oblateness of the Earth. The method is applied to eliminate relative secular drifts in the case when a satellite is controlled using an engine mounted along its orientation axis (the satellite is supplied with a passive magnetic attitude control system) and with the help of a solar sail installed on one of the satellites. Analytical results are confirmed by numerical simulation.     

Scattering function of tropospheric aerosol according to the data of polarimetry of the twilight and night sky background

The paper contains the photometric and polarimetric analysis of the sky background near the zenith during the twilights and the nights of different years and seasons. The period of enhanced tropospheric aerosol content during the summer 2009 is noticed. The aerosol scattering of solar emission is separated from the total twilight sky background, and similar data on lunar emission is taken from the night sky background. The results are compared with the data of relatively clear troposphere of winter 2006. The observational data are used to construct the polarization scattering function of tropospheric aerosol particles during the nighttime.