Rychlé až velmi rychlé procesy na úrovni organismů nebo tkání jsou v biologii velmi časté. Kamery specializované na vysokorychlostní video jsou velmi drahé. Některé současné a relativně levné digitální fotoaparáty dokáží pořizovat videosekvence při vysoké rychlosti (zatímco 30 snímků za sekundu je standardní rychlost, tyto moderní fotoaparáty dokáží snímat až 1200 snímků za sekundu). and Rapid and very rapid processes at the level of the entire organism as well as at the tissue level are very common in biology. Some recent and relatively cheap digital cameras enable biologists to shoot videosequences at a high rate (while 30 frames per second is the standard rate, such modern cameras go up to 1 200 fps).
Weathering and erosion of sandstone landscapes often results in many amazing landforms such as arches, alcoves (rock shelters), pedestal rocks and pillars. Long-term research has produced numerous contrasting ideas for the origin of these landforms. The presence of salt and/or occurrence of freezing water and/or similar potential weathering/erosion processes at site are common causes of these landforms. The effect of gravity loading stress has been overlooked or assumed to increase the landform’s weathering rate. Research at the Institute of Rock Structure and Mechanics is based on field observations of locked sands and cemented sandstones and on physical experiments, followed by a numerical modelling. This may be the first time that the landforms cited above were reproduced in laboratory experiments. The Institute interpreted its findings by a novel mechanical model called “the concept of locus of fabric instability.” The results clearly show that an increase in stress within the landform (fabric interlocking) reduces weathering and erosion. Material with insufficient loading is rapidly removed by that weathering process and the remaining load bearing landform structure is protected by the fabric interlocking mechanism. The Institute concludes that its research that planar discontinuities in sandstone and negative feedback between stress and weathering/erosion processes are sufficient conditions to create landforms. and Michal Filippi, Jana Schweigstillová.