The CAT Imaging Telescope for Very-High-Energy Gamma-Ray Astronomy

The CAT (Cherenkov Array at Themis) imaging telescope, equipped with a very-high-definition camera (546 fast phototubes with 0.12 degrees spacing surrounded by 54 larger tubes in two guard rings) started operation in Autumn 1996 on the site of the former solar plant Themis (France). Using the atmospheric Cherenkov technique, it detects and identifies very high energy gamma-rays in the range 250 GeV to a few tens of TeV. The instrument, which has detected three sources (Crab nebula, Mrk 421 and Mrk 501), is described in detail.Comment: 24 pages, 15 figures. submitted to Elsevier Preprin

Measuring the propensity to drink and drive

Laws such as .08 blood alcohol content, open container, and license revocation provide a policy framework for reducing drinking and driving. Drinking and driving behavior is difficult to assess; unlike property and violent crimes, where incidence statistics can approximate behavior, most drink-driving trips go undetected. The authors develop a novel measure of drink-driving propensity by estimating an item response model using national survey data. The authors illustrate their measures in the aggregate and as they relate to law enforcement efforts in the American states