The prevalence of MDMA/MDA in both hair and urine in drug users

The prevalence and age distribution of 3,4-methylenedioxymethamphetamine (MDMA) and 3,4-methylenedioxyamphetamine (MDA) in hair samples by gas chromatography/mass spectrometry (GC/MS) were studied. The recoveries obtained from hair were 97% and 99% for MDMA and MDA, respectively. The inter- and intra-assay precision and accuracy were determined. Out of 791 hair samples, 44 (5.6 %) contained MDMA and/or MDA. Out of these 44 subjects, urinalyses from 35 were negative for both MDMA and MDA, while only 9 were positive. We also evaluated concentrations of MDMA and MDA, and the metabolite-to-parent drug ratios. This study showed that the abuse of MDMA or MDA was found principally among young adults and male abusers. We found the epidemiology of ecstasy users in Korea between March 2002 and April 2003.     

An empirical testing of leverage effects via the common distribution network

The paper aims to empirically test the significance of leverage effects via the common distribution network in the conglomerate mergers between beer and soju manufacturers of Korea in the time period of 1994–2003. In this paper, a beer (or soju) manufacturer's ability to push the sales of soju (or beer) products via the common regional liquor distribution network is measured by the beer (or soju) firm's market share in the region. If the leverage effect is significant, we expect consumer choices to be significantly affected by the merged firm's ability to push. For a consistent estimation of the leverage effect on consumer demands, this paper adapts a logistic demand function for Yellow Pages in Rysman [Rysman, M. (2004). Competition between networks: A study of the market for yellow pages. Review of Economic Studies, 71, 483–512], controlling other demand-side variables such as prices, consumer loyalty, quality and the introduction of new products. The hypothesis test results indicate that the leverage effects via the common distribution network were not significant at the significance level of 0.1. This conclusion is robust to different specifications of leverage effects and the number of potential drinking.