0000000000430164
AUTHOR
Alexandra M. Freund
showing 4 related works from this author
Cross-Sectional and Longitudinal Associations between Leisure Time Physical Activity, Mental Well-Being and Subjective Health in Middle Adulthood
2019
Previous studies have shown that participation in leisure time physical activity is related to better mental well-being and subjective health. However, the associations between different types of leisure time physical activities and different dimensions of mental well-being have rarely been studied. In addition, longitudinal research, analyzing possible causal relations between these variables, is lacking. To investigate these research questions, data gathered at ages 42 and 50 (present N = 303) for the Finnish Jyväskylä Longitudinal Study of Personality and Social Development were used. Physical activity was assessed as frequency of participation at ages 42 and 50, and at age 50 also as fr…
Major results from the first plasma campaign of the Wendelstein 7-X stellarator
2017
After completing the main construction phase of Wendelstein 7-X (W7-X) and successfully commissioning the device, first plasma operation started at the end of 2015. Integral commissioning of plasma start-up and operation using electron cyclotron resonance heating (ECRH) and an extensive set of plasma diagnostics have been completed, allowing initial physics studies during the first operational campaign. Both in helium and hydrogen, plasma breakdown was easily achieved. Gaining experience with plasma vessel conditioning, discharge lengths could be extended gradually. Eventually, discharges lasted up to 6 s, reaching an injected energy of 4 MJ, which is twice the limit originally agreed for t…
LEISURE TIME PHYSICAL ACTIVITY, LEISURE SATISFACTION AND SUBJECTIVE WELL-BEING: CAUSAL RELATIONSHIPS IN MIDLIFE
2018
Participation in leisure time physical activity (LTPA) in midlife is linked to both current well-being and many future benefits in older age. However, longitudinal analyses of the causal links between LTPA and well-being are lacking. Therefore, the aim of this study was to investigate longitudinal associations between LTPA and subjective well-being in middle adulthood. In addition, the role of leisure satisfaction in these relationships were investigated. The data gathered at ages 42 and 50 for the Finnish Jyväskylä Longitudinal Study of Personality and Social Development were used (present N=303). LTPA was asked as frequency of participation and leisure satisfaction as general satisfaction…
Overview of first Wendelstein 7-X high-performance operation
2019
Abstract The optimized superconducting stellarator device Wendelstein 7-X (with major radius , minor radius , and plasma volume) restarted operation after the assembly of a graphite heat shield and 10 inertially cooled island divertor modules. This paper reports on the results from the first high-performance plasma operation. Glow discharge conditioning and ECRH conditioning discharges in helium turned out to be important for density and edge radiation control. Plasma densities of with central electron temperatures were routinely achieved with hydrogen gas fueling, frequently terminated by a radiative collapse. In a first stage, plasma densities up to were reached with hydrogen pellet injec…