Electron temperature gradient (ETG)-driven turbulence, despite its ultrafine scale, is thought to drive significant thermal losses in magnetic fusion devices-but what role does it play in ...stellarators? The first numerical simulations of ETG turbulence for the Wendelstein 7-X stellarator, together with power balance analysis from its initial experimental operation phase, suggest that the associated transport should be negligible compared to other channels. The effect, we argue, originates essentially from the geometric constraint of multiple field periods, a generic feature of stellarators.
An increasing body of research indicates that use of electronic nicotine delivery systems (ENDS) predicts cigarette initiation. However, no studies examine if risk for cigarette initiation varies for ...exclusive ENDS users versus users of ENDS and other tobacco products. This study examined if: a) cigarette-naïve young adults (i.e., never cigarette users) who ever used ENDS had a greater odds of initiating cigarettes than non-ENDS users over a 1.5year period and b) the odds of cigarette initiation was consistent across exclusive ENDS users and users of ENDS and at least one tobacco product.
Participants were 2558 cigarette-naïve 18–25year old (M=19.71; SD=1.61) students from 24 Texas colleges who participated in a four-wave study, with six months between each wave.
Overall, 11% of students reported cigarette initiation by wave 4. Of those, 20.1% were wave 1 ENDS users and 8.4% were non-ENDS users. Multivariable, multilevel discrete-time hazard models indicated that wave 1 ENDS use predicted subsequent cigarette initiation, over and above the significant effects of cigarette use susceptibility, family-of-origin tobacco use, friend cigarette use, and other tobacco use. Additional findings indicated that exclusive ENDS users had a greater odds than non-users of subsequent cigarette initiation. Among users of alternative tobacco products, ENDS users did not have a greater odds of initiation than non-ENDS users.
Findings extend existing research by showing that ENDS use by young adults is a specific risk factor for later cigarette initiation and not an extension of a constellation of existing tobacco use behaviors.
•11% of college students initiated cigarette use over the 1.5year study period.•More ENDS users than non-users initiated cigarette use during the study period.•Exclusive ENDS use predicted subsequent cigarette initiation.
Highlights • We examine the temporal relation between energy drink and alcohol use among youth. • Energy drink at baseline is positively related with alcohol use at follow-up. • The relation remains ...while controlling for socio-economic status, previous alcohol use, and impulsivity. • Alcohol use prevention efforts should consider energy drinks as risk factors.
The soft x-ray tomography diagnostic in the stellarator Wendelstein 7-X consists of twenty pinhole cameras, up-down symmetrically arranged in a poloidal, triangular cross-section of the plasma ...vessel. The x-ray emissivity is measured with 16 bit amplitude resolution at 2 MHz sampling rate along 360 lines-of-sight by silicon photodiode arrays. In the recent operation campaign data acquisition (DAQ) has been working reliable for the conducted plasma pulse lengths <1 min, however the DAQ system are ready for the foreseen 30 min plasma pulse lengths of upcoming campaigns. The bandwidth of the preamplifiers is 200 kHz and the sensitive energy range is approximately 1-12 keV. The measurements indicate the up-down symmetric emissivity distribution in the triangular poloidal cross-section. First tomographic reconstructions of different magnetic field configurations are consistent with the theoretically calculated flux surface topology.
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