On the Bayesian analysis of species sampling mixture models for density estimation

The mixture of normals model has been extensively applied to density estimation problems. This paper proposes an alternative parameterisation that naturally leads to new forms of prior distribution. The parameters can be interpreted as the location, scale and smoothness of the density. Priors on these parameters are often easier to specify. Alternatively, improper and default choices lead to automatic Bayesian density estimation. The ideas are extended to multivariate density estimation

Bayesian Stochastic Frontier Analysis Using WinBUGS

Markov chain Monte Carlo (MCMC) methods have become a ubiquitous tool in Bayesian analysis. This paper implements MCMC methods for Bayesian analysis of stochastic frontier models using the WinBUGS package, a freely available software. General code for cross-sectional and panel data are presented and various ways of summarizing posterior inference are discussed. Several examples illustrate that analyses with models of genuine practical interest can be performed straightforwardly and model changes are easily implemented.Efficiency, Markov chain Monte Carlo, Model comparison, Regularity, Software

Yield losses caused by late blight (Phytophthora infestans (Mont.) de Bary) in potato crops in Ireland

peer-reviewedField experiments, using foliage blight susceptible cultivars, were conducted at Oak Park, Carlow from 1983 to 2007 to determine the loss in potato production caused by crop infection with Phytophthora infestans. In each of the 25 years an untreated control was compared with protectant and with systemic fungicide programmes to determine the effect of late blight on the defoliation percentage at the end of the season, the area under the disease progress curve, marketable tuber yield, total tuber yield and yield of blighted tubers. The earliest date of first recorded late blight was 22 June and the latest was 15 September, but in 15 of the 25 years, blight was first recorded between 17 July and 13 August. Disease reached epidemic proportions in all but 4 of the years. Yields varied considerably among years. The mean loss in total yield from not using a fungicide was 10.1 t/ha. Differences in yield were significant across the 25 seasons. No overall increase in aggressiveness of the pathogen could be detected over the 25-year period

Bayesian inference with stochastic volatility models using continuous superpositions of non-Gaussian Ornstein-Uhlenbeck processes

This paper discusses Bayesian inference for stochastic volatility models based on continuous superpositions of Ornstein-Uhlenbeck processes. These processes represent an alternative to the previously considered discrete superpositions. An interesting class of continuous superpositions is defined by a Gamma mixing distribution which can define long memory processes. We develop efficient Markov chain Monte Carlo methods which allow the estimation of such models with leverage effects. This model is compared with a two-component superposition on the daily Standard and Poor's 500 index from 1980 to 2000.Leverage effect; Levy process; Long memory; Markov chain Monte Carlo; Stock price

Priming Past the Primary: Mass Media, Issue Salience and Candidate Evaluation in a Race Governor

Past research indicates that voters have begun to rely less on party affiliations and more on candidates\u27 images and positions on issues in making voting decisions. Through using the mass media, voters can learn about issues and candidates, and form images of the candidates. Our study concerns the effects of mass mediated election news, and of political advertising, on voters\u27 choice of candidates. In particular, we examined the roles of media agenda-setting and priming, and of negative political advertising, in the development of voter’s evaluations of candidates. An important trend in agenda-setting research is to look beyond issue saliences as dependent variables to determine what relationships issue saliences have with other phenomena, such as public opinion and voting choice. Research into priming indicates that the issues and other aspects of political life (e.g., a candidate\u27s character) that become salient in an election are used by voters to evaluate candidates for public office, and therefore indirectly affect voting behavior. An analysis of a sample survey of eligible voters in the 1990 race for Wisconsin governor found that attention to news accounts of the election is associated with higher levels of salience given some issues in that election. In line with the priming model, issue salience had some, although modest, relationship to evaluation of the candidates. Political commercials, including negative ads, appeared to affect candidate evaluations more directly, while news media appeared to work through issue salience to affect evaluations of candidates. Some evidence was found of a \u27\u27boomerang effect of negative advertising in this campaign. Identification with political parties had only a small direct relationship to voting intention. Instead, this identification appears to work along with the direct and indirect effects of communication variables to influence candidate evaluation, which then appears to affect voting choice

The Relationship of Fans’ Sports-Team Identification and Facebook Usage to Purchase of Team Products

Social media has become a regular direct marketing component for sports teams. This study explores the link between team identification and use of a professional sports team’s social-media channels. Questions to answer include, Does social media impact identification fans have with a team or vice versa? What does the amount of social-media use do to impact the relationship? Does this activity lead to increased sales of tickets and merchandise? Data collected by an Internet survey of fans of a professional baseball team show a positive relationship between team identification and use of the team’s Facebook page as well as to team related purchases. Implications for theorists understanding the role of social media in branding as well as implications for sports marketing are discussed