A computer method that is used to control call center volumes for a range of dates. The bushes are arranged so that the stem can be installed on the support plate in an assembly direction perpendicular to the support plate and the locking component includes, between the two bearing elements, a recess allowing the insertion of the stem into the recess simultaneously with the installation of the stem on the support plate. The collected data pertaining to a group of individuals who are present near the display device, is processed and used to select appropriate advertisements that would most likely interest that group of individuals. A long-pass filter in the return path attenuates light in the second spectral range.