Locomotion, facilitation

Cells respond to some extracellular factors such as leukotriene B (Ford-Hutchin-son et al., 1980) by increasing the locomotion rate in an undirected manner as opposed to chemotaxis. This mechanism, known as chemokinesis, is likely on purely statistical grounds to result in cells accumulating at the site of origin of this stimulus (Wilkinson, 1987). The differentiation of factors that are chemotactic from chemokinetic responses can be difficult, but this has been greatly facilitated using the Boyden chamber (Lackie, 1986). 

Female rats are more active than males in tests of locomotion (Wang 1923 Beatty 1979 Burke and Broadhurst 1966 Cronan et al. 1985 Rodier 1971 van Haaren and Meyer 1991 Kanyt et al. 1999 Booze et al. 1999, Harrod et al. 2004). This sex difference is markedly reduced in gonadectomized female rats, suggesting a role for ovarian hormones (Kanyt et al. 1999 Booze et al. 1999). In a pioneering study, Rosecrans (1972) had shown that nicotine facilitated spontaneous locomotor activity in females, but had no effect in males. 

The development of the types of skeletons that characterize Tommotian faunas constituted a major evolutionary event. Although skeletons are known to support soft tissue and to facilitate locomotion, such adaptive functions cannot explain why so many different kinds of skeletons developed suddenly in the early part of Tommotian time. It has been suggested that a chemical change within the oceans triggered the production of these skeletons, but this hypothesis does not explain why some skeletons were composed of calcium carbonate and others of calcium phosphate, two compounds with quite different chemical properties. The rapid evolution of various kinds of external skeletons is probably in part attributable to the fact that animals... 

A risk assessment team was estabhshed consisting of a mechanical engineer, the colliery safety engineer, an tmdemtartager, a deputy and a locomotive driver and facilitated by the Head of Ergonomics and Safety Management. 

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