Determination of mouth alcohol using the Dräger Evidential Portable Alcohol System

Drivers suspected of alcohol intoxication are observed for a period of 15 min prior to quantitative breath alcohol testing. This is to preclude the interference of alcohol-based substances such as cough medicine, mouthwash, and breath spray just prior to actual evidential testing. To determine whether a 15 min observation period was necessary when performing evidential breath tests in the field, a mouth alcohol experiment was performed using the Dräger Evidential Portable Alcohol System (EPAS). Five types of alcohol beverages and the effects of expectorating versus swallowing were tested on twenty-five volunteer subjects. Serial measurements of breath and blood alcohol levels were performed at fixed time intervals. All alcohol beverage types gave two sequential measurements within 0.02 g/210 L of each other before 15 min had passed. Fifteen minutes was necessary to ensure there was no residual mouth alcohol. If the 15 min waiting period was not observed, the safety feature of the EPAS requiring two sequential measurements 2 min apart within 0.02 g/210 L would not ensure against mouth alcohol interference.     

Reference ballistic imaging database performance

Ballistic imaging databases allow law enforcement to link recovered cartridge cases to other crime scenes and to firearms. The success of these databases has led many to propose that all firearms in circulation be entered into a reference ballistic image database (RBID). To assess the performance of an RBID, we fired 4200 cartridge cases from 600 9mm Para Sig Sauer model P226 series pistols. Each pistol fired two Remington cartridges, one of which was imaged in the RBID, and five additional cartridges, consisting of Federal, Speer, Winchester, Wolf, and CCI brands. Randomly selected samples from the second series of Remington cartridge cases and from the five additional brands were then correlated against the RBID. Of the 32 cartridges of the same make correlated against the RBID, 72% ranked in the top 10 positions. Likewise, of the 160 cartridges of the five different brands correlated against the database, 21% ranked in the top 10 positions. Generally, the ranking position increased as the size of the RBID increased. We obtained similar results when we expanded the RBID to include firearms with the same class characteristics for breech face marks, firing pin impressions, and extractor marks. The results of our six queries against the RBID indicate that a reference ballistics image database of new guns is currently fraught with too many difficulties to be an effective and efficient law enforcement tool.     

Group Structure and Intergroup Relations in Global Terror Networks: Further Explorations

Studies have begun to look at the potentially crucial impacts of group decentralization and inter-group global networking in accounting for the extent and severity of violence in insurgencies and terrorism. Groups may be able to survive more effectively, evade anti-terror or counter-insurgency strategies, and inflict greater damage or more civilian attacks by operating under more or less centralized leadership, or by making use of the resources of other like-minded groups scattered across borders. While some analysts have examined each of these possibilities, few if any have done so simultaneously with both structural and networking indicators or examined the joint effects of these indicators. We propose to do so in this study by combining existing datasets on terrorist structure and networks. Hypotheses and findings in prior studies have indicated that structural decentralization may lead to more civilian attacks if not more destruction since local cells are freer to act on their own, and that group size and centrality in the global terror networks lead to greater lethality and group survival rates. We re-examine such assumptions here with OLS and logit models combining these effects, and find that in addition to group size, network reach (eigenvalue centrality) rather than group interconnections per se (number of allies) appears to have primary impacts on group lethality, targeting, and survival, sometimes in conjunction with decentralized organizational structure.