The market for social norms

This article presents a semirigorous model in which a new normarises out of the workings of a market for norms. Change istriggered by a shift in either cost-benefit conditions or groupcomposition. Because individuals are heterogeneous in importantrespects, they respond differently to these triggering events.The first persons to supply new norms generally are individualswho have either superior technical knowledge of cost-benefitconditions, superior social knowledge of group dynamics, orspecial endowments that provide them with unusually high tangiblebenefits from norm reform. Members of the social audience observethe competing efforts of these norm suppliers and reward themost meritorious ones by conferring on them either esteem or,according to an alternative conception, new exchange opportunities.Under optimal conditions, members of the audience - key participantsin the demand side of the market for norms - do not free-ridebecause they incur no net costs when conferring their rewards.     

Method for characterization of adhesion properties of trace explosives in fingerprints and fingerprint simulations

The near inevitable transfer of explosive particulate matter through fingerprints makes it possible to detect concealed explosives through surface sampling. Repeatable and well-characterized fingerprint simulation facilitates quantitative comparison between particulate sampling methods for subsequent detection of trace explosive residues. This study employs a simple, but reproducible sampling system to determine the accuracy of a fingerprint simulation. The sampling system uses a gas jet to entrain particles from a substrate and the resulting airborne particles are then aspirated onto a Teflon filter. A calibrated Barringer IonScan 400 ion mobility spectrometer was used to determine the mass of explosive material collected on the filter. The IonScan 400 was calibrated with known masses of 2,4,6-trinitrotoluene (TNT). The resulting calibration curve is in good agreement with that obtained by Garofolo et al. (1994) for an earlier model of the instrument. The collection efficiency of the sampling system was measured for three particle sizes (8.0. 10.0, and 13.0 microm) using spherical polystyrene particles laced with known quantities of TNT. Collection efficiency ranged from less than 1% for the larger particles to 5% for the smaller particles. Particle entrainment from the surface was monitored with dark field imaging of the remaining particles. The sampling system was then applied to two C4 test samples--a fingerprint transfer and a dry Teflon transfer. Over 100 ng of RDX was collected from the dry transfer sample, while less than 1 ng was collected from the fingerprint transfer. Possible explanations for this large difference are presented based on the system calibration.