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The suggestion that utility is logically necessary for behavioural adjustments to be made in response to changes in intrinsic risk is fundamental to risk homeostasis theory (RHT). However, the methodology used to investigate RHT — analysis of road traffic accidents — is ill-suited to the investigation of this assertion. The role of utility and intrinsic risk as possible determinants of behavioural compensation were therefore examined experimentally across 14 specific behaviours using the Aston Driving Simulator. RHT predicts that these two factors act in a multiplicative way to form a statistical interaction. It also predicts that the behavioural pathways through which the effect manifests itself should be reconcilable with the concept of utility. Both predictions received little support in this experiment, suggesting that utility and intrinsic risk operate as independent factors: both factors produced significant main effects across a number of behaviours. This finding, if it can be generalised, implies that, contrary to mathematically-based models of danger compensation and the traditional model of risk homeostasis, utility is not logically necessary for behavioural compensation in response to a change in intrinsic risk. 相似文献
854.
Risk homeostasis theory (RHT) suggests that changes made to the intrinsic risk of environments are negated in one of three ways: behavioural adjustments within the environment, mode migration, and avoidance of the physical risk. To date, this three-way model of RHT has little empirical support, whilst research findings on RHT have at times been diametrically opposed. A reconciliation of apparently opposing findings might be possible by suggesting that extrinsic compensation fails to restore previously existing levels of actual risk in cases where behavioural adjustments within the environment are incapable of negating intrinsic risk changes. This paper reports a study in which behavioural adjustments within the physical risk-taking environment are capable of reconciling target with actual risk. The results provide positive support for RHT in the form of overcompensation for the intrinsic risk change on specific driver behaviours. 相似文献
855.
Peter J. Taylor Glen R. Walker Geoff Hodgson Thomas J. Hatton Ray L. Correll 《Environmental management》1996,20(4):553-564
Irrigated agriculture has resulted in substantial changes in water flows to the lower reaches of the River Murray. These changes have led to large-scale occurrences of dieback inEucalyptus largiflorens (black box) woodlands as well as increased inputs of salt to the river. Management options to address problems of this scale call for the use of spatial data sets via geographic information systems (GIS). A GIS exists for one floodplain of the River Murray at Chowilla, and a simple model predicted six health classes ofEucalyptus largiflorens based on groundwater salinity, flooding frequency, and groundwater depth.To determine the usefulness of the model for vegetation management, the quality of both the model and the GIS data sets were tested. Success of the testing procedure was judged by the degree of spatial matching between the model's predictions of health and that assessed from aerial photographs and by field truthing. Analyses at 80 sites showed that tree health was significantly greater where groundwater salinity was less than 40 dS/m or flooding occurred more frequently than 1 in 10 years or depth to groundwater exceeded 4 m. Testing of the GIS data sets found that vegetation was misclassified at 15% of sites. Association was shown between GIS-predicted values and field-truthed values of groundwater salinity but not groundwater depth. The GIS model of health is a useful starting point for future vegetation management and can be further improved by increasing the quality of the data coverages and further refining of the model to optimize parameters and thresholds. 相似文献
856.
Ajit K. Chowdhury Thomas R. Stolzenburg Robert R. Stanforth Michael A. Warner Mark E. Larowe 《补救:环境净化治理成本、技术与工艺杂志》1996,6(2):15-21
The sediment associated with the reconstruction of a bridge pier was classifiable as hazardous by the Toxicity Characteristic Leaching Procedure (TCLP), due to elevated concentrations of lead. However, RCRA regulations do not classify the sediment as hazardous unless it is moved. RMT designed an in-situ, underwater treatment process to render the sediment nonhazardous, using phosphate-based chemistry before dredging. Subsequent sediment management was conducted without the additional regulatory requirements and costs associated with managing hazardous waste. 相似文献
857.
Arthur J. Morgan J. L. Thomas 《Journal of the American Water Resources Association》1973,9(5):884-891
ABSTRACT: There is a lamentable absence of comprehensive planning in the current cursade to improve water quality. A serious shortcoming is the lack of evaluation of the effects of waste water treatment upon environmental quality. At some point in time the public may ask what they have obtained for their money. The nature of pollution in a river basin demands a coordinated attack against it. Engineering and economic criteria suggest that a properly empowered river basin authority would be the logical organization to plan and operate a water quality management system. Several forms of such authorities have operated effectively and efficiently for many years in the United States and other industrialized countries. Examples of successful river basin authorities and their advantages and methods of operation are discussed. 相似文献
858.
Thomas R. Burke 《Journal of the American Water Resources Association》1970,6(4):661-681
With the increasing Federal role in all aspects of water resource planning, the need for a planning model to enable calculations of projected Municipal Water requirements has become evident. This study represents an initial effort at developing an econometric model of Municipal Water requirements which (1) incorporates variables (or proxies) reflecting the various factors affecting water demand (i.e., demographic, social, industrial), and (2) requires only readily available, published data for its use. This model permits determinations of the water requirements of 488 cities grouped into 19 geographic regions or “Pseudo States.” Separate regression functions have been fitted to the cities within each of the 19 regions. Derivation of the exact functions for each region entailed a cross section stepwise regression analysis in which some 18 different variables were examined. KEY WORDS: planning model; econometric model; initial effort; municipal water 相似文献
859.
Thomas M. Scherer R. Clinton Fuller Robert W. Lenz Steve Goodwin 《Journal of Polymers and the Environment》1999,7(3):117-125
A strain of Aspergillus fumigatus, which was observed to rapidly degrade poly-3-hydroxybutyrate (PHB) in a leaf compost, was found to secrete an extracellular hydrolase when grown on PHB as the sole carbon source. Isolation and characterization of the PHB hydrolase (depolymerase) from this fungus revealed that the enzyme had a molecular weight of 57 kDa, an isoelectric point of 7.2, and a PHB hydrolysis activity maxima which occurred at 70°C and pH 8.0. Affinity labeling experiments suggested that this fungal hydrolase is a type of serine esterase. The cyclic trimers of 3-hydroxybutyrate were found to reversibly inhibit the enzymes. 相似文献
860.