RESUMO
The 8.4 eV nuclear isomer state in Th-229 is resonantly excited in Th-doped CaF_{2} crystals using a tabletop tunable laser system. A resonance fluorescence signal is observed in two crystals with different Th-229 dopant concentrations, while it is absent in a control experiment using Th-232. The nuclear resonance for the Th^{4+} ions in Th:CaF_{2} is measured at the wavelength 148.3821(5) nm, frequency 2020.409(7) THz, and the fluorescence lifetime in the crystal is 630(15) s, corresponding to an isomer half-life of 1740(50) s for a nucleus isolated in vacuum. These results pave the way toward Th-229 nuclear laser spectroscopy and realizing optical nuclear clocks.
RESUMO
Changes in work ability and work interest (meaning) after the participation in a health promotion program were perceived and evaluated. Drivers of the Munich Transport Authority (n = 122) of an average age of 50 years participated in 20 health days during working time over 1 year. The evaluation instruments of the health promotion program were the Work Ability Index (WAI) developed by the Finnish Institute of Occupational Health (FIOH) and the Effect Typology developed by the Institute of Occupational Health Promotion (IBG Austria). No changes were found in the WAI score. The Effect Typology evaluated the optimal effect "evolution," i.e., psychological and noetic (mental) changes, for 50% of the participants. A variance analysis of the WAI pre-post differences according to the effect classes of the Effect Typology showed significant differences, namely an increase in the WAI in the evolution group and a drop in the recovery group. The Effect Typology is suitable for the evaluation of occupational health promotion and for the further understanding and development of the WAI.