This paper examines the relation between prices in conventional stores and on the Internet. Main results from the theoretical analysis are i) we expect a discrete fall in prices in conventional stores as the share of the population with access to Internet reaches a critical level, ii) the...

Over recent years, several nonlinear time series models have been proposed in the literature. One model that has found a large number of successful applications is the threshold autoregressive model (TAR). The TAR model is a piecewise linear process whose central idea is to change the parameters...

We performed a cross-sectional, "bottom-up" observational study of resource consumption and quality of life of patients with multiple sclerosis (MS) in the United Kingdom. Three centers participated in the study. Patients received a questionnaire either by mail or during a clinic visit, and a...

We performed a cross-sectional, "bottom-up" observational study of resource consumption and quality of life of patients with multiple sclerosis (MS) in Germany. Six centers participated in the study. Patients were asked to complete a questionnaire, and a total of 737 patients returned the...