A proper understanding of tissue and cell structure is of great importance for correct biological inferences, and particularly so in organisms used as research models. Nothobranchius spp. are short-lived freshwater fish species which are promising model organisms for toxicology, evolutionary ecology, aging and regeneration research. Nevertheless, studies examining Nothobranchius histology have focused exclusively on a few specific organs and associated functional impairments, and there is a lack of reference material on the natural state and appearance of tissue structure. Here we present a detailed histological map of the major body organ systems, which was built from 300 Nothobranchius spp. specimens. This overview offers baseline material for comparative histological studies and provides insights into functional and anatomical aspects of organs related to the unique life cycle of Nothobranchius spp.
For small meteoric bodies, terminating high in the atmosphere (i.e.
under free molecular conditions) it was possible to neglect the effect of thermal motions of air particles. As regards fireballs, bodies with masses in excess of about 0.1 kg, penetrating deep into the atnosphere, the ambient atmosphere has the properties of a continuous medium. Under these conditions, the thermal motions of atmospheric particles behind ťhe shock wave become
the decisive factor for momentum and energy transfer to the meteoroid. F'or fireballs these thermal motions practically replace the effect of direct impacts of particles of hie undisturbed atmosphere, considered earlier under free molecular conditions. The form of the equations, describing the motion and ablation of a large body (fireball) will remain the same as for small bodies, but the coefficients occurring in the equations will have a different
physical meaning.