Fear of crime in Brisbane - Individual, social and neighbourhood factors in perspective

Numerous theories apply to fear of crime and each are associated with different kinds of variables. Most studies use only one theory, though this study examines the relative importance of different kinds of variables across a number of theories. The study uses data from a survey of residents in Brisbane, Australia to examine the relative importance of individual attributes, neighbourhood disorder, social processes and neighbourhood structure in predicting fear of crime. Individual attributes and neighbourhood disorder were found to be important predictors of fear of crime, while social processes and neighbourhood structure were found to be far less important. The theoretical implications are that the vulnerability hypothesis and the incivilities thesis are most appropriate for investigating fear of crime, though social disorganization theory does provide conceptual support for the incivilities thesis. Although social processes are less important in predicting fear of crime than neighbourhood incivilities, they are still integrally related to fear of crime: they explain how incivilities arise, they buffer against fear of crime, and they are affected by fear of crime.

Anaerobic metabolism of propionate by polyphosphate-accumulating organisms in enhanced biological phosphorus removal systems

Propionate, a carbon substrate abundant in many prefermenters, has been shown in several previous studies to be a more favorable substrate than acetate for enhanced biological phosphorus removal (EBPR). The anaerobic metabolism of propionate by polyphosphate accumulating organisms (PAOs) is studied in this paper. A metabolic model is proposed to characterize the anaerobic biochemical transformations of propionate uptake by PAOs. The model is demonstrated to predict very well the experimental data from a PAO culture enriched in a laboratory-scale reactor with propionate as the sole carbon source. Quantitative fluorescence in-situ hybridization (FISH) analysis shows that Candidatus Accumulibacter phosphatis, the only identified PAO to date, constitute 63% of the bacterial population in this culture. Unlike the anaerobic metabolism of acetate by PAOs, which induces mainly poly-beta-hydroxybutyrate (PHB) production, the major fractions of poly-beta-hydroxyalkanoate (PHA) produced with propionate as the carbon source are poly-beta-hydroxyvalerate (PHV) and poly-beta-hydroxy-2-methylvalerate (PH2MV). PHA formation correlates very well with a selective (or nonrandom) condensation of acetyl-CoA and propionyl-CoA molecules. The maximum specific propionate uptake rate by PAOs found in this study is 0.18 C-mol/C-mol-biomass h, which is very similar to the maximum specific acetate uptake rate reported in literature. The energy required for transporting 1 carbon-mole of propionate across the PAO cell membrane is also determined to be similar to the transportation of 1 carbon-mole of acetate. Furthermore, the experimental results suggest that PAOs possess a similar preference toward acetate and propionate uptake on a carbon-mole basis. (c) 2005 Wiley Periodicals, Inc.