Extra safety measures like solar fences, concrete posts and ditches have been dug up around vulnerable communities.

Ayrton's interest in vortices in water and air inspired the Ayrton fan, or flapper, used in the trenches in the First World War to dispel poison gas.

On the Western Front the small improvised trenches of the first few months rapidly grew deeper and more complex, gradually becoming vast areas of interlocking defensive works.

The training schedule has been accelerated as a result, five battalions (or kandaks) representing a total of 3,000 soldiers, are trained simultaneously. Upon graduation, kandaks are deployed to the regional corps to undertake joint operations with the coalition forces.

Additionally, the federal government has resolved to dispatch police forces to oversee security in Iguala, after the discovery of six unmarked graves in the settlement of Pueblo Viejo, including the mangled remains of a youth identified as a student in a nearby industrial neighborhood.

Plans to train six kandaks at a time, to be implemented in March 2005, will enable the Afghan National Army to reach its target of 70,000 troops in December 2006.

A small portion of the wall in urban areas including East Jerusalem about 30 km, according to Israeli officials is 8.5 m high the rest consists of a 50 m wide buffer zone of ditches, trenches, wires and electronic fences, including monitoring and detection systems.6 According to a witness, the wall in the Gaza Strip alone was expected to be 102 km long with a portion possibly extending into the sea.