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. Author manuscript; available in PMC: 2021 Sep 1.
Published in final edited form as: J Safety Res. 2020 Jul 10;74:169–177. doi: 10.1016/j.jsr.2020.06.003

Fig. 2.

Fig. 2.

The experimental protocol. The KSS questionnaire, biomarkers, and performance data were collected six times throughout the 20-week protocol on the last two shifts of the baseline assessment and lighting intervention periods. Six series of data were collected per shift, twice during each of the shift’s first (T1), middle (T2), and final (T3) hours, with the first series (T1a, T2a, T3a) separated from the second (T1b, T2b, T3b) by 30-min intervals within each hour. The PSQI, PROMIS-SD, and PROMIS-GH questionnaires were filed during the final hour of the baseline and intervention periods.