Robust automatic mapping algorithms in a network monitoring scenario

Automatically generating maps of a measured variable of interest can be problematic. In this work we focus on the monitoring network context where observations are collected and reported by a network of sensors, and are then transformed into interpolated maps for use in decision making. Using traditional geostatistical methods, estimating the covariance structure of data collected in an emergency situation can be difficult. Variogram determination, whether by method-of-moment estimators or by maximum likelihood, is very sensitive to extreme values. Even when a monitoring network is in a routine mode of operation, sensors can sporadically malfunction and report extreme values. If this extreme data destabilises the model, causing the covariance structure of the observed data to be incorrectly estimated, the generated maps will be of little value, and the uncertainty estimates in particular will be misleading. Marchant and Lark [2007] propose a REML estimator for the covariance, which is shown to work on small data sets with a manual selection of the damping parameter in the robust likelihood. We show how this can be extended to allow treatment of large data sets together with an automated approach to all parameter estimation. The projected process kriging framework of Ingram et al. [2007] is extended to allow the use of robust likelihood functions, including the two component Gaussian and the Huber function. We show how our algorithm is further refined to reduce the computational complexity while at the same time minimising any loss of information. To show the benefits of this method, we use data collected from radiation monitoring networks across Europe. We compare our results to those obtained from traditional kriging methodologies and include comparisons with Box-Cox transformations of the data. We discuss the issue of whether to treat or ignore extreme values, making the distinction between the robust methods which ignore outliers and transformation methods which treat them as part of the (transformed) process. Using a case study, based on an extreme radiological events over a large area, we show how radiation data collected from monitoring networks can be analysed automatically and then used to generate reliable maps to inform decision making. We show the limitations of the methods and discuss potential extensions to remedy these.

The pharmacist's contribution towards monitoring and reporting adverse drug reactions

The activities and function of the West Midlands Adverse Drug Reaction Study Group are described. The impact of the Group on the reporting of adverse drug reactions to the CSM by the yellow card system has been evaluated in several ways including a comparison with the Trent Region. The role of the pharmacist in the Group is highlighted. A nationwide survey of the hospital pharmacist's involvement in adverse drug reaction reporting and monitoring is described, the results are reported and discussed. The available sources of information on adverse drug reactions, both primary and secondary, are critically reviewed. A checklist of necessary details for case reports is developed and examples of problems in the literature are given. The contribution of the drug information pharmacist in answering enquiries and encouraging reporting is examined. A role for the ward pharmacist in identifying, reporting, documenting and following up adverse drug reactions is proposed. Studies conducted to support this role are described and the results discussed. The ward pharmacist's role in preventing adverse drug reactions is also outlined. The reporting of adverse drug reactions in Australia is contrasted with the U.K. and particular attention is drawn to the pharmacist's contribution in the former. The problems in evaluating drug safety are discussed and examples are given where serious reactions have only been recognised after many patients have been exposed. To remedy this situation a case is made for enhancing the CSM yellow card scheme by further devolution of reporting, increasing the involvement of pharmacists and improving arrangements at the CSM. It is proposed that pharmacists should undertake the responsibility for reporting reactions to the CSM in some instances.