Injuries and use of protective equipment among college in-line skaters

In-line skating injuries and protective gear use were explored in a sample of college students (n = 217). A minority of respondents wore protective gear. One third of skaters had experienced at least one minor injury, and a smaller percentage had experienced fractures or head injuries. Most minor injuries occurred during the first 1–2 times skating, while more serious injuries tended to occur after at least 50 times on in-line skates. Psychosocial predictors of protective gear use were explored. Four major Health Belief Model constructs (perceived barriers to wearing gear, perceived susceptibility to injury, perceived severity of injury, and perceived benefits of wearing gear) were significant predictors of protective gear use. The Health Belief Model, tested using regression and structural equation modelling, predicted gear typically worn, frequency of gear use, and injuries received while in-line skating. Implications for increasing protective gear use are described.     

Naphthenic acids and surrogate naphthenic acids in methanogenic microcosms.

Naphthenic acids (NAs) are a complex mixture of naturally occurring acyclic and cyclic aliphatic carboxylic acids in petroleum. In the Athabasca oil sands. NAs have been identified as the largest component of dissolved organic matter in the tailings waters from oils sands extraction processes. They are the major contributor to the acute toxicity of the fine tailings wastewaters at the oil sands extraction plants in northeastern Alberta, Canada. In this study, three sources of NAs were studied, including commercially available NAs, those extracted from oil sands process-affected waters, and individual naphthenic-like surrogate compounds. Analysis by gas chromatography-mass spectrometry demonstrated differences between the commercial and extracted NAs. The NAs derived from the process-affected waters showed a short-term inhibition of methanogenesis from H2 or acetate, but with time the populations resumed methane production. It has been postulated that microbial metabolism of the carboxylated side chains of NAs would lead to methane production. The two NA mixtures failed to stimulate methanogenesis in microcosms that contained either oil sands fine tailings or domestic sewage sludge. However, in microcosms with sewage sludge, methanogenesis was stimulated by some surrogate NAs including 3-cyclohexylpropanoic acid at 400-800 mg/L, 5-cyclohexylpentanoic acid at 200 mg/L or 6-phenylhexanoic acid at 200 and 400 mg/L. When added at 200 mg/L to methanogenic microcosms containing fine tailings, 3-cyclohexylpropanoic and 4-cyclohexylbutanoic acids produced methane yields that suggested mineralization of the side chain and the ring.     

Reformulating and testing the perfectionism model of binge eating among undergraduate women: A short-term, three-wave longitudinal study.

The perfectionism model of binge eating (PMOBE) is an integrative model explaining why perfectionism is related to binge eating. This study reformulates and tests the PMOBE, with a focus on addressing limitations observed in the perfectionism and binge-eating literature. In the reformulated PMOBE, concern over mistakes is seen as a destructive aspect of perfectionism contributing to a cycle of binge eating via 4 binge-eating maintenance variables: interpersonal discrepancies, low interpersonal esteem, depressive affect, and dietary restraint. This test of the reformulated PMOBE involved 200 undergraduate women studied using a 3-wave longitudinal design. As hypothesized, concern over mistakes appears to represent a vulnerability factor for binge eating. Bootstrapped tests of mediation suggested concern over mistakes contributes to binge eating through binge-eating maintenance variables, and results supported the incremental validity of the reformulated PMOBE beyond perfectionistic strivings and neuroticism. The reformulated PMOBE also predicted binge eating, but not binge drinking, supporting the specificity of this model. The reformulated PMOBE offers a framework for understanding how key contributors to binge eating work together to generate and to maintain binge eating. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Oscillating Combustion of Gun Propellants in the Closed Vessel. I. preliminary investigation

The oscillating combustion, which takes place in the closed vessel when certain colloidal gun propellants are fired has been investigated. The amplitude of the oscillation depended on the geometry and flame temperature of the propellant. For propellants having the same composition but different geometry, the amplitude of the oscillation varied inversely with the maximum pressure in the vessel. This was tentatively ascribed to vortex formation during combustion.