TR 19 dealt with excavations in just two adjacent residential compounds, groups 4F-1 and 4F-2 (thus designated from their locations in square 4F of the alphanumeric grid
of the TR 11 map), situated close to the Tikal Project camp; many of the protocols for dealing with Tikal's small structures were established here in the 1959-1960 investigations.
Together with clear, alphanumeric grid
referencing, this ensures that valuable PCR and qPCR samples are protected and easily located.
By requiring different combinations from the Entrust IdentityGuard alphanumeric grid
to answer each randomized challenge, attackers have little probability of successfully intercepting a login and using it to subsequently gain access to a user's account.
Grid work: How to be organized on the job -- An alphanumeric grid
and more than 30 other systems teaches students how to organize, classify and retrieve technical information.