Molecular diameters of rarefied gases.

Molecular diameters are an important property of gases for numerous scientific and technical disciplines. Different measurement techniques for these diameters exist, each delivering a characteristic value. Their reliability in describing the flow of rarefied gases, however, has not yet been discussed, especially the case for the transitional range between continuum and ballistic flow. Here, we present a method to describe gas flows in straight channels with arbitrary cross sections for the whole Knudsen range by using a superposition model based on molecular diameters. This model allows us to determine a transition diameter from flow measurement data that paves the way for generalized calculations of gas behaviour under rarefied conditions linking continuum and free molecular regime.

The association of cognitive distortions and the type of gambling in problematic and disordered gambling.

BACKGROUND: Previous studies have shown that particular types of gambling are related to the development of gambling-related problems. Further, gambling-related cognitive distortions contribute to the development of disordered gambling. The aim of the present study is to compare different gambling types with respect to cognitive distortions and the development of disordered gambling. METHODS: Based on a proactively screened sample of vocational school students (N = 6718), 309 students were selected to undergo an in-depth interview. We assessed the Gamblers-Belief-Questionnaire (GBQ) to measure gambling-related cognitive distortions and the Stinchfield questionnaire for assessing gambling-related problems. Associations between cognitive distortions, gambling-related symptoms, and types of gambling were analysed using logistic regression analyses. RESULTS: Higher scores on the GBQ subscale "belief in luck/perseverance" led to a significantly higher chance to be classified as a person with Gambling Disorder (Conditional Odds Ratio (COR) = 1.05, Confidence Interval (CI) = 1.02-1.08) as well as problematic gambling (COR = 1.04, CI = 1.01-1.06). Higher scores on the subscale "illusion of control" were also associated with problematic gambling (COR = 1.04, CI = 1.00-1.08). The multivariate analyses of the gambling types identified only sports betting as a predictor for problematic gambling (COR = 1.91, CI = 1.05-3.49). When controlling for cognitive distortions, sports betting was not significant anymore. With respect to disordered gambling, gambling on electronic gambling machines (EGMs) turned out to be a risk factor besides cognitive distortions (COR = 2.59, CI = 1.04-6.49). DISCUSSION: The present study confirmed the high relevance of cognitive distortions for problematic and disordered gambling especially for sports betting and gambling on EGMs. Preventive measures and psychotherapy should take these relationships into account.