Learn More
Preparing the German Spacelab Mission D-2 project "Gravity Perception and Neuronal Plasticity"--STATEX II--ground based experiments have been performed with larvae of the amphibian vertebrate Xenopus laevis Daud. to study the reactions to different levels of acceleration forces and profiles. The larvae have been exposed to accelerations of up to 5 g for(More)
The paper sums up results of a 7-day space flight experiment (D-l-Mission-BW-STA 00-STATEX) using growing frog embryos and larvae (Xenopus laevis) as a model system. Evaluation of photographs taken from the surface of sectioned deep-frozen objects, and micrographs using TEM and SEM show no aberrations in the shape, size, position, or respective electron(More)
This paper builds on initial work on specifying robot motion using human-inspired motor programs. The existing method relies on a series of square wave torque pulses to actuate the robot. Using such pulses to produce motions with a robot will generate large peaks in absolute jerk — change in acceleration per unit time — which can damage the(More)
O ne possibility of analyzing the formation of organisms is the investigation of functional ripening of cells and organs in a stimulus-free environment. For example, the optical centers of vertebrates attain their final functional performance only under stimulus from the optical environment. The information content of the genome is evidently not sufficient(More)
Organisms use gravity for spatial orientation, and differentiation into species during evolution follows geological processes which are caused by gravity. On the other hand, the task of most organismic functions which have or may have a relation to gravity is to compensate gravity. Furthermore, today it is very obvious that organisms do not disintegrate(More)
The paper describes an investigation of the influence of gravity on the early differentiation of gravity receptors in Xenopus embryos and larvae. There is evidence that the expression of crystals in the saccus endolymphaticus was statistically greater when the embryos developed in near weightlessness (hypogravity) than on earth. The function of these(More)
limonene/ozone (Table 2). Ozone production rates ([03]ma × divided by irradiation time) for linalool ranged from 0.32 to 0.39 ppb rain -1 and are comparable to those found by the photooxidation of toluene and isoprene (0.36 to 0.45ppbmin -1) and higher than the corresponding values measured for aand fl-pinene (0.1 to 0.24 ppb min-1). Changes in relative(More)
A theoretical model is presented that describes the volume scattering in thin optical films, particularly in typical columnar structures. It is based on a first-order perturbation theory that concerns the fluctuation of the dielectric permittivity in the film. For evaporated PbF(2) films that show a pronounced columnar morphology, angular as well as total(More)
The vestibular apparatus of tadpoles (Rana temporaria) exposed to simulated weightlessness was examined by electron microscopy. Extended exposure to simulated weightlessness is followed by significant alterations in the sensory epithelia and also in the otolith membrane. Large vacuoles, filled with necrobiotic mitochondria and fragments of endoplasmic(More)
Cichlid fish larvae were reared from hatching to active free swimming under different gravity conditions: natural environment, increased acceleration in a centrifuge, simulated weightlessness in a clinostat and near weightlessness during space flight. Cytochrome oxidase activity was analyzed semiquantitatively on the ultrastructural level as a marker of(More)