Formation and growth of callus tissue of Arabidopsis under changed gravity.

The changed gravity conditions do not prevent the process of cell dedifferentiation and formation of callus. Yet, callus grown on the clinostat and in space differs from the control one: its consistence is denser, occurence of meristematic centres is less frequent and it shows a reduced proliferative activity of cells. Average size of cell and nuclei area in the test variants is lower than in the control.     

Coronal Mass Ejections

This workshop summary tries to distill the key difficulties and questions in the art of (I)CME physics and strategies to address them. (I)CMEs are multi-dimensional, multi-parameter, and multi-scale phenomena related to the solar dynamo, corona, and heliosphere. This workshop illustrates the immense progress made in describing and modeling these spectacular energetic solar events, but also shows clear shortcomings in our understanding of them.     

Amphibian tail regeneration in space: effect on the pigmentation of the blastema.

In Urodele amphibians, the tail regenerates after section. This regeneration, including tissues as different as bone (vertebrae), muscle, epidermis and central nervous system (spinal cord), was studied in adult Pleurodeles sent aboard the russian satellite Bion 10 and compared with tail regeneration in synchronous controls. Spinal cord, muscle and cartilage regeneration occurred in space animals as in synchronous controls. One of the most important differences between the two groups was the pigmentation of the blastemas: it was shown in laboratory, to be not due to a difference in light intensity.     

Theoretical model of HZE particle fragmentation by hydrogen targets.

The fragmenting of high energy, heavy ions (HZE particles) by hydrogen targets is an important, physical process in several areas of space radiation research. In this work quantum mechanical optical model methods for estimating cross sections for HZE particle fragmentation by hydrogen targets are presented. The cross sections are calculated using a modified abrasion-ablation collision formalism adapted from a nucleus-nucleus collision model. Elemental and isotopic production cross sections are estimated and compared with report measurements for the breakup of neon, sulphur, and iron, nuclei at incident energies between 400 and 910 MeV/nucleon. Good agreement between theory and experiment is obtained.     

ROSAT observations of X-ray sources in globular clusters

We review the first observations of globular clusters obtained with the X-ray telescope on board of the ROSAT satellite. In the All-Sky Survey, all known bright sources and two new transient sources were detected. In addition a super-soft source was found in NGC5272. Concerning the dim sources, the survey suggests that those outside the core of ω Cen are not related to the cluster. The survey further improved by one or two magnitudes on many upper limits previously obtained by the HEAO-1 satellite. Pointed observations have improved the positional accuracy of a number of sources, and added to the number of known dim sources. In 47 Tuc, the known central source is resolved into 4 separate sources, which we argue are all soft X-ray transients. A comparison with observations of the old open cluster M67 leads us to suggest that some of the dim sources may be conglomerates of a large number of RS Can Ven type binaries.     

A compact dopplergraph/magnetograph suitable for space-based measurements of solar oscillations and magnetic fields

A compact Dopplergraph/magnetograph placed in a continuous solar-viewing orbit will allow us to make major advancements in our understanding of solar internal structure and dynamics. An international program is currently being conducted at JPL and Mt. Wilson to develop such an instrument. By combining a unique magneto-optical resonance filter with CID and CCD cameras we have been able to obtain full- and partial-disk Dopplergrams and magnetograms. Time series of the velocity images are converted into k-ω power spectra which show clear- the solar nonradial p-mode oscillations. Magnetograms suitable for studying the long-term evolution of solar active regions have also been obtained with this instrument. A flight instrument based on this concept is being studied for possible inclusion in the SOHO mission.     

Radiation effects on late cytopathological parameters in the murine lens relative to particle fluence.

Lenses of mice irradiated with 250 MeV protons, 670 MeV/amu 20Ne, 600 MeV/amu 56Fe, 600 MeV/amu 93Nb and 593 MeV/amu 139La ions were evaluated by analyzing cytopathological indicators which have been implicated in the cataractogenic process. The LETs ranged from 0.40 keV/micrometer to 953 keV/micrometer and fluences from 1.31 10(3)/mm2 to 4.99 x 10(7)/mm2. 60Co gamma-rays were used as the reference radiation. The doses ranged from 10 to 40 cGy. The lenses were assessed 64 weeks post irradiation in order to observe the late effects of LET and dose on the target cell population of the lens epithelium. Our study shows that growth dependent pathological changes occur at the cellular level as a function of dose and LET. The shapes of the RBE-LET and RBE-dose curves are consistent with previous work on eye and other biological systems done in both our laboratory and others. The RBEmax's were estimated, for the most radiation cataract related cytological changes, MN frequency and MR disorganization, by calculating the ratio of the initial slopes of dose effect curve for various heavy ions to that of 60Co gamma-ray. For each ion studied, the RBEmax derived from micronucleus (MN) frequency is similar to that derived from meridional row (MR) disorganization, suggesting that heavy ions are equally efficient at producing each type of damage. Furthermore, on a per particle basis (particle/cell nucleus), both MN frequency and MR disorganization are LET dependent indicating that these classic precataractogenic indicators are multi-gene effects. Poisson probability analysis of the particle number traversing cell nuclei (average area = 24 micrometers2) suggested that single nuclear traversals determine these changes. By virtue of their precataractogenic nature the data on these endpoints intimate that radiation cataract may also be the consequence of single hits. In any case, these observations are consistent with the current theory of the mechanism of radiation cataractogenesis, which proposes that genomic damage to the epithelial cells surviving the exposure is responsible for opacification.     

Orbiting VLBI

The technique of Michelson interferometry using synchronized radio telescope systems at great separations is known as Very-Long-Baseline Interferometry (VLBI). The method can be extended to give micro-arc-second angular resolution by using radio telescopes in space. There are no technical barriers, and several classes of conceptual systems can be specified.     

Vertical density and temperature structure over Northern Europe

During the Energy Budget Campaign, several profiles of the density and temperature of the upper atmosphere were obtained. The measurements were made using rocket-borne instrumentation launched from ESRANGE, Sweden and Andoya Rocket Range, Norway during November and December, 1980. The techniques included meteorological temperature sondes, passive falling spheres, accelerometer instrumented falling spheres, density gauges, mass spectrometers and infrared emission experiments. The instruments provided data within the altitude range from 20 km to 150 km. The measurements were made during periods which have been grouped into three categories by level of geomagnetic activity. Analysis has been made to compare the results and to examine the oscillations and fluctuations in the vertical profiles for scales ranging between hundreds of meters and tens of kilometers. Most of the features observed fit qualitatively within the range expected for internal gravity waves. The geomagnetic storm conditions may be associated with enhanced wave activity and heating observed in the lower thermosphere.     

Instrument concept and preliminary performance analysis of GLORIA

The Global Radiance Limb Imager Experiment for the Atmosphere (GLORIA) shall provide a detailed global picture of the upper troposphere/lower stratosphere region (UTLS) and make available novel information on small-scale atmospheric dynamics.

The instrument will be a space borne imaging Fourier Transform Spectrometer operating in the thermal infrared spectral region. It will produce spectrally resolved images of the earth’s limb with a vertical extension of 60 km and a horizontal extension of 400 km. The paper focuses on the preliminary instrument concept and on results of studies concerning sensitivity and spectrometric performance. GLORIA has been proposed as a national German space mission. An aircraft version is currently under development.