Detection of outliers in simple circular regression models using the mean circular error statistic

The investigation on the identification of outliers in linear regression models can be extended to those for circular regression case. In this paper, we propose a new numerical statistic called mean circular error to identify possible outliers in circular regression models by using a row deletion approach. Through intensive simulation studies, the cut-off points of the statistic are obtained and its power of performance investigated. It is found that the performance improves as the concentration parameter of circular residuals becomes larger or the sample size becomes smaller. As an illustration, the statistic is applied to a wind direction data set.     

On Non-parametric Estimation of the Survival Function with Competing Risks

The non-parametric maximum likelihood estimators (MLEs) are derived for survival functions associated with individual risks or system components in a reliability framework. Lifetimes are observed for systems that contain one or more of those components. Analogous to a competing risks model, the system is assumed to fail upon the first instance of any component failure; i.e. the system is configured in series. For any given risk or component type, the asymptotic distribution is shown to depend explicitly on the unknown survival function of the other risks, as well as the censoring distribution. Survival functions with increasing failure rate are investigated as a special case. The order restricted MLE is shown to be consistent under mild assumptions of the underlying component lifetime distributions.     

The Ecology of Suicide in an Australian Metropolis: The Case of Sydney

The ecological patterns of suicide in metropolitan Sydney are described and policy recommendations made. Some inferences about the association of urbanization with suicide are suggested.     

Maximum entropy sampling and optimal Bayesian experimental design

When Shannon entropy is used as a criterion in the optimal design of experiments, advantage can be taken of the classical identity representing the joint entropy of parameters and observations as the sum of the marginal entropy of the observations and the preposterior conditional entropy of the parameters. Following previous work in which this idea was used in spatial sampling, the method is applied to standard parameterized Bayesian optimal experimental design. Under suitable conditions, which include non-linear as well as linear regression models, it is shown in a few steps that maximizing the marginal entropy of the sample is equivalent to minimizing the preposterior entropy, the usual Bayesian criterion, thus avoiding the use of conditional distributions. It is shown using this marginal formulation that under normality assumptions every standard model which has a two-point prior distribution on the parameters gives an optimal design supported on a single point. Other results include a new asymptotic formula which applies as the error variance is large and bounds on support size.     

Expert Study to Select Indicators of the Occurrence of Emerging Mycotoxin Hazards

This article describes a Delphi‐based expert judgment study aimed at the selection of indicators to identify the occurrence of emerging mycotoxin hazards related to Fusarium spp. in wheat supply chains. A panel of 29 experts from 12 European countries followed a holistic approach to evaluate the most important indicators for different chain stages (growth, transport and storage, and processing) and their relative importance. After three e‐mailing rounds, the experts reached consensus on the most important indicators for each of the three stages: wheat growth, transport and storage, and processing. For wheat growth, these indicators include: relative humidity/rainfall, crop rotation, temperature, tillage practice, water activity of the kernels, and crop variety/cultivar. For the transport and storage stage, they include water activity in the kernels, relative humidity, ventilation, temperature, storage capacity, and logistics. For wheat processing, indicators include quality data, fraction of the cereal used, water activity in the kernels, quality management and traceability systems, and carryover of contamination. The indicators selected in this study can be used in an identification system for the occurrence of emerging mycotoxin hazards in wheat supply chains. Such a system can be used by risk managers within governmental (related) organizations and/or the food and feed industry in order to react proactively to the occurrence of these emerging mycotoxins.     

The Psychodynamics of Consensual Sadomasochistic and Dominant-Submissive Sexual Games

The author examines a case from a qualitative research study exploring repetition-compulsion and repair in consensual sadomasochistic/dominant-submissive (SMDS) sexual play. The study attempts to bridge the epistemological divide between clinically derived psychoanalytic theories about perversion and nonclinical research on consensual SMDS subcultures. The case addresses research questions about the presence of, and possibilities for, working through childhood developmental conflicts in consensual SMDS (as theoretically differentiated from its nonconsensual counterparts).

This study, along with those theories that uproot classical notions of sexuality and the “oedipal divide,” lends support for the view that the diversity of lived and practiced sexualities defies facile categorization and that, if categorization is to be attempted, it must take into account individual meanings and relational/larger social contexts.     

Living Behind Dikes: Mimicking Flooding Experiences

Delta areas like the Netherlands are threatened by global climate change. Awareness is, however, rather low. Our research objective was to investigate whether coping responses to flooding risks could be enhanced in a virtual environment (VE). A laboratory experiment was conducted in which participants were exposed to a simulated dike breach and consequent flooding of their virtual residence. We tested the hypothesis that an interactive 3D flood simulation facilitates coping responses compared to noninteractive film and slide simulations. Our results showed that information search, the motivation to evacuate, and the motivation to buy flood insurance increased after exposure to the 3D flood simulation compared to the film and slide simulations. Mediation analyses revealed that some of these presentation mode effects were mediated by a greater sense of being present in the VE. Implications to use high‐end flood simulations in a VE to communicate real‐world flooding risks and coping responses to threatened residents will be discussed.