Scientific perspectives are important in the discussion of specific periods (not unspecified period as you have done) like the last 18 years compared to the last 36 and like the period since 1850 as compared to natural temperature cycles of the geologic timescales. (wattsupwiththat.com)
On his return to work, his employer did not allow him to return to the full range of his duties, but instead proposed a reduced responsibility role for a temporary but unspecified period so he could get back up to speed and prove himself after a long period of absence. (hcrlaw.com)