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The modern theory of likelihood inference provides improved inferences in many parametric models, with little more effort than is required for application of standard first-order theory. We outline the relevant computations, and illustrate the calculations using a dilution assay, a zero-inflated Poisson regression model, and a short time series. In each case the effect of the higher order correction can be appreciable. KEY WORDS: Autoregression; Bias reduction; Dilution assay; Higher order asymptotics; Likelihood; Zero-inflated Poisson distribution.

A class of models for discretized series of events based on a suggestion from Davison (1984) is proposed. The models are based on a doubly stochastic Poisson process with an arrival rate dependent on an unobserved continuous-time Markov chain in a finite state space. The processes can be adopted to produce binary time series models for single and multiple series of events controlled by a common underlying process., 1. INTRODUCTION Discretized data arise in many environmental applications. For example, rainfall occurs in continuous space and time, but it is usually recorded at a single site and aggregated over [...]

Abstract: Wine production is an important industry in Western Switzerland, but vineyards must contend with grape vine and grape berry moths, the larval stages of which feed on grape flower buds and berries. This paper proposes a stochastic model for prediction of the emergence times of the moths, in order to aid treatment aimed at their control. Observed moth counts are treated as a realization of an inhomogeneous Poisson process whose probabilities are related to the distribution of time to emergence. We use a hierarchical model to account for the variability of this distribution between sites and years. Maximum likelihood and Bayesian fitting of the model to data are described, the latter using Markov chain Monte Carlo simulation, and the Bayesian approach is used for forecasting in future years. Grape vine moth flights proved much more variable than grape berry moth flights among sites and years; depending on the site, the flights of the two species can overlap or be completely distinct. Credibility intervals are provided for each site for a random future year, and the predictions can be updated and refined once 15–20% of the flight for a new year has emerged. The paper ends with discussion of the role of such models in similar applications. [Copyright &y& Elsevier]

Behavioural assays to study insect attraction to specific odours are tedious, time consuming and often require large numbers of replications. Olfactometer and flight tunnel tests can usually only be conducted with one or two odour sources at a time. Moreover, chemical information on the odour sources has to be obtained in separate analytical studies. An olfactometer was developed in which six odours can be tested simultaneously for their relative attractiveness while during the assays, part of each test odour can be trapped for further analyses. The effectiveness of this six-arm olfactometer was tested by observing the responses of the solitary endoparasitoid Cotesia marginiventris (Cresson) to host-induced odours from young maize plants. For statistical analyses, we used log-linear models were adapted to account for overdispersion and possible positional biases. Female wasps responded extremely well in tests where they were offered a single odour source, as well as in tests with multiple choices. The responses of wasps released in groups were the same as those released individually and it was found that females did not attract or repel each other, but males preferred arms in which females had been released. Dose response tests with varying numbers of plants or host larvae on plants revealed that the wasps responded in a dose-related manner, thus showing that the system is well suited to measure relative preference. The clear choices of the insects amongst six possibilities provided substantial statistical power. Gas chromatographic analyses of sampled air revealed clean and effective odour trapping, which largely facilitates the comparison of results from behavioural assays with the actual blends of volatiles that were emitted by the various odour sources. Advantages and disadvantages compared to other methods are discussed. [ABSTRACT FROM AUTHOR]

Provides information on the activities of the editors of the 'Journal of the Royal Statistical Society' in 2002. Retirement and recruitment of several editors for the journal; Number of papers submitted to the journal as of August 2002; Information on the average time from acceptance to publication of submitted articles.