Spatio-temporal scanning and statistical test of the accelerating moment release (AMR) model using Australian earthquake data

The Accelerating Moment Release (AMR) preceding earthquakes with magnitude above 5 in Australia that occurred during the last 20 years was analyzed to test the Critical Point Hypothesis. Twelve earthquakes in the catalog were chosen based on a criterion for the number of nearby events. Results show that seven sequences with numerous events recorded leading up to the main earthquake exhibited accelerating moment release. Two occurred near in time and space to other earthquakes preceded by AM R. The remaining three sequences had very few events in the catalog so the lack of AMR detected in the analysis may be related to catalog incompleteness. Spatio-temporal scanning of AMR parameters shows that 80% of the areas in which AMR occurred experienced large events. In areas of similar background seismicity with no large events, 10 out of 12 cases exhibit no AMR, and two others are false alarms where AMR was observed but no large event followed. The relationship between AMR and Load-Unload Response Ratio (LURR) was studied. Both methods predict similar critical region sizes, however, the critical point time using AMR is slightly earlier than the time of the critical point LURR anomaly.

Adsorption of benzene on graphitized thermal carbon black: Reduction of the quadrupole moment in the adsorbed phase

The performance of intermolecular potential models on the adsorption of benzene on graphitized thermal carbon black at various temperatures is investigated. Two models contain only dispersive sites, whereas the other two models account explicitly for the dispersive and electrostatic sites. Using numerous data in the literature on benzene adsorption on graphitized thermal carbon black at various temperatures, we have found that the effect of surface mediation on interaction between adsorbed benzene molecules must be accounted for to describe correctly the adsorption isotherm as well as the isosteric heat. Among the two models with partial charges tested, the WSKS model of Wick et at. I that has only six dispersive sites and three discrete partial charges is better than the very expensive all-atom model of Jorgensen and Severance.(2) Adsorbed benzene molecules on graphitized thermal carbon black have a complex orientation with respect to distance from the surface and also with respect to loading. At low loadings, they adopt the parallel configuration relative to the graphene surface, whereas at higher loadings (still less than monolayer coverage) some molecules adopt a slant orientation to maximize the fluid-fluid interaction. For loadings in the multilayer region, the orientation of molecules in the first layer is influenced by the presence of molecules in the second layer. The data that are used in this article come from the work of Isirikyan and Kiselev,(3) Pierotti and Smallwood,(4) Pierce and Ewing,(5) Belyakova, Kiselev, and Kovaleva,(6) and Carrott et al.(7)

Aggressive behaviour in the high-secure forensic setting: the perceptions of patients

Twenty-seven patients undergoing treatment in a high-secure forensic facility participated in focus group interviews to elicit their perceptions of (1) the factors leading to aggressive behaviour; and (2) strategies to reduce the risk of such behaviour. The focus group interviews were audiotaped, transcribed and analysed using content analysis. The participants identified that a combination of patient, staff and environmental factors contributed to violence in the study wards. The cause of aggressive behaviour centred around five major themes: the environment; empty days; staff interactions; medication issues; and patient-centred factors. Potential strategies identified by patients to reduce aggressive behaviour included: early intervention; the provision of meaningful activities to reduce boredom; separation of acutely disturbed patients; improved staff attitudes; implementation of effective justice procedures; and a patient advocate to mediate during times of conflict. Findings suggested that social and organizational factors need to be addressed to change the punitive subculture inherent in forensic psychiatric facilities, and to ensure a balance between security and effective therapy.

A study of organizational citizenship behaviors in a retail setting

This study investigates the potential antecedents of organizational citizenship behaviors (OCBs) in a retail setting. Much remains unknown about the factors affecting OCBs in retail settings. Several characteristics of retail jobs, as compared with other organizational behavior contexts, suggest the need to examine antecedents of OCBs. Job attitudes (job satisfaction and organizational commitment) are proposed as direct predictors of OCBs. Leadership support, professional development, and empowerment are posited as indirect predictors of OCBs and direct predictors of job attitudes. The possible moderating impacts of employee demographics and job types on the modeled relationships are also examined. The research hypotheses are tested using data collected from 211 frontline employees who work in a retail setting. The employees have customer-contact roles in the upscale food and grocery retailer that participated in the study. The pattern of results is more complex than hypothesized. Job attitudes are related to OCBs but the mediating role of job attitudes is not supported. The relationships between leadership support, professional development, and empowerment, and OCBs and job attitudes differ systematically. Evidence of how employee demographics can alter the modeled relationships is also presented. The findings have significant implications for the theory and practice of managing frontline employees. Limitations of the study are discussed and a program of further research is sketched. (C) 2003 Elsevier Inc. All rights reserved.

The burden of major depression avoidable by longer-term treatment strategies

Background: Major depression is the largest single cause of nonfatal disease burden in Australia. Effective drug and psychological treatments exist, yet are underused. Objective: To quantify the burden of disease currently averted in people seeking care for major depression and the amount of disease burden that could be averted in these people under optimal episodic and maintenance treatment strategies. Design: Modeling impact of current and optimal treatment strategies based on secondary analysis of mental health survey data, studies of the natural history of major depression, and meta-analyses of effectiveness data. Monte Carlo simulation of uncertainty in the model. Setting: The cohort of Australian adults experiencing an episode of major depression in 2000 are modeled through "what if" scenarios of no treatment, current treatment, and optimal treatment strategies with cognitive behavioral therapy or antidepressant drug treatment. Main Outcome Measure: Disability-Adjusted Life Year. Results: Current episodic treatment averts 9% (95% uncertainty interval, 6%-12%) of the disease burden of major depression in Australian adults. Optimal episodic treatment with cognitive behavioral therapy could avert 28% (95% uncertainty interval, 19%-39%) of this disease burden, and with drugs 24% (95% uncertainty interval, 19%-30%) could be averted. During the 5 years after an episode of major depression, current episodic treatment patterns would avert 13% (95% uncertainty interval, 10%-17%) of Disability-Adjusted Life Years, whereas maintenance drug treatment could avert 50% (95% uncertainty interval, 40%-60%) and maintenance cognitive behavioral therapy could avert 52% (95% uncertainty interval, 42%-64%), even if adherence of around 60% is taken into account. Conclusions: Longer-term maintenance drug or psychological treatment strategies are required to make significant inroads into the large disease burden associated with major depression in the Australian population.

On the possibility of elastic strain localisation in a fault

The phenomenon of strain localisation is often observed in shear deformation of particulate materials, e.g., fault gouge. This phenomenon is usually attributed to special types of plastic behaviour of the material (e.g., strain softening or mismatch between dilatancy and pressure sensitivity or both). Observations of strain localisation in situ or in experiments are usually based on displacement measurements and subsequent computation of the displacement gradient. While in conventional continua the symmetric part of the displacement gradient is equal to the strain, it is no longer the case in the more realistic descriptions within the framework of generalised continua. In such models the rotations of the gouge particles are considered as independent degrees of freedom the values of which usually differ from the rotation of an infinitesimal volume element of the continuum, the latter being described for infinitesimal deformations by the non-symmetric part of the displacement gradient. As a model for gouge material we propose a continuum description for an assembly of spherical particles of equal radius in which the particle rotation is treated as an independent degree of freedom. Based on this model we consider simple shear deformations of the fault gouge. We show that there exist values of the model parameters for which the displacement gradient exhibits a pronounced localisation at the mid-layers of the fault, even in the absence of inelasticity. Inelastic effects are neglected in order to highlight the role of the independent rotations and the associated additional parameters. The localisation-like behaviour occurs if (a) the particle rotations on the boundary of the shear layer are constrained (this type of boundary condition does not exist in a standard continuum) and (b) the contact moment-or bending stiffness is much smaller than the product of the effective shear modulus of the granulate and the square of the width of the gouge layer. It should be noted however that the virtual work functional is positive definite over the range of physically meaningful parameters (here: contact stiffnesses, solid volume fraction and coordination number) so that strictly speaking we are not dealing with a material instability.

The role of BNP testing in heart failure

Brain natriuretic peptide (BNP) levels are simple and objective measures of cardiac function. These measurements can be used to diagnose heart failure, including diastolic dysfunction, and using them has been shown to save money in the emergency department setting. The high negative predictive value of BNP tests is particularly helpful for ruling out heart failure. Treatment with angiotensin-converting enzyme inhibitors, angiotensin-II receptor blockers, spironolactone, and diuretics reduces BNP levels, suggesting that BNP testing may have a role in monitoring patients with heart failure. However, patients with treated chronic stable heart failure may have levels in the normal range (i.e., BNP less than 100 pg per mL and N-terminal proBNP less than 125 pg per mL in patients younger than 75 years). Increases in BNP levels may be caused by intrinsic cardiac dysfunction or may be secondary to other causes such as pulmonary or renal diseases (e.g., chronic hypoxia). BNP tests are correlated with other measures of cardiac status such as New York Heart Association classification. BNP level is a strong predictor of risk of death and cardiovascular events in patients previously diagnosed with heart failure or cardiac dysfunction.

Using Developmental Theories to Inform the Design of Technology for Children

Electronic Blocks are a new programming environment, designed specifically for children aged between three and eight years. As such, the design of the Electronic Block environment is firmly based on principles of developmentally appropriate practices in early childhood education. The Electronic Blocks are physical, stackable blocks that include sensor blocks, action blocks and logic blocks. Evaluation of the Electronic Blocks with both preschool and primary school children shows that the blocks' ease of use and power of engagement have created a compelling tool for the introduction of meaningful technology education in an early childhood setting. The key to the effectiveness of the Electronic Blocks lies in an adherence to theories of development and learning throughout the Electronic Blocks design process.