Activation - dependent changes in receptor distribution and dendritic morphology in hippocampal neur

Mechanisms for joining two telescopic cylinders underwater in a temporary and inexpensive manner are disclosed, particularly when used in anchoring piles or in offshore tower legs. A gun fires projectiles radially from internally of the pile formed of telescopic cylinders to form the plurality of outwardly extending anchoring bumps in the walls of the cylinders. The projectiles are fired in a horizontal plane radially outwardly and from within and normal to the two telescopic cylinders underwater, for example, with two bumps being formed by each projectile, which bumps overlie each other tightly prior to their being penetrated by the projectile which holds the two bumps together. A number of radiating guns form a like number of pairs of bumps in a circle around the periphery of the telescopic cylinders to form an efficient, inexpensive, and simple temporary connection holding the two cylinders together. After forming the bumps in the buried pile cylinders and simultaneously packing the soil around them, each projectile penetrates its bump and packed soil to provide a pile or offshore tower legs with high resistance to separation of the telescoped cylinders forming the pile or offshore tower legs, with increased load-carrying-capacity and with increased resistance-to-pull-out.