Ice-Casts of Tracks

Ice-wedge Casts of Wisconsinan Age in Eastern Nebraska

Sand-filled, wedge-shaped structures beneath a thin layer of aeolian sand penetrate a preIllinoian till and gravel in northeastern Nebraska. Interpreted to be relic thermal contraction crack wedges, they provide the first definite evidence in this State of the former presence of permafrost. The wedges are 57 m apart, 1.8-2.8 m deep and 0.6-0.9 m across at the top, taper downward to a crack and ...

Particle emission induced by ionization tracks in water ice

We study electron emission and sputtering during irradiation of amorphous water ice at 60 K by HC, DC, He+, Li+, Be+, B+, C+, N+, O+, F+, and Ne+ ions in the energy range from 10 to 100 keV. We find that for constant velocity (5 keV/amu) ions the dependence of the sputtering yields with projectile atomic number Z is proportional to the square of the Z-dependence of the electronic stopping power...

Analysis of Arterial Casts

In the region from arterial trunks to pial arterioles anatomical characteristics of the cerebral artery as revealed by quantitative treatment of the arterial cast consist in the predominance of the length of large arterial branches over that of the arterioles. Theoretical analysis of blood pressure drop based on the above result demonstrates a large pressure drop in the region of large arterial...

The evolution of bronchial casts.

The mammalian lung provides a system of airways in which inspired air is brought into intimate contact with the blood. As well as carrying out this essential physiological function, the hollow structure of the lung has enabled investigators to produce casts of the airways, the study of which has helped in the understanding of air movements within the lung. The dependence of higher forms of life...

Hair casts (pseudonits).