Correction to: Improved X-ray baggage screening sensitivity with 'targetless' search training.

Funder: Defence and Security Accelerator; doi: http://dx.doi.org/10.13039/100012339Abstract: When searching for a known target, mental representations of target features, or templates, guide attention towards matching objects and facilitate recognition. When only distractor features are known, distractor templates allow irrelevant objects to be recognised and attention to be shifted away. This is particularly true in X-ray baggage search, a challenging real-world visual search task with implications for public safety, where targets may be unknown, difficult to predict and concealed by an adversary, but distractors are typically benign and easier to identify. In the present study, we draw on basic principles of distractor suppression and rejection to investigate a counterintuitive ‘targetless’ approach to training baggage search. In a simulated X-ray baggage search task, we observed significant benefits to target detection sensitivity (d′) for targetless relative to target-based training, but no effects of performance-contingent rewards or the inclusion of superordinate semantic categories during training. The benefits of targetless search training were most apparent for stimuli involving less spatial overlap (occlusion), which likely represents the difficulty and greater individual variation involved in searching more visually complex images. Together, these results demonstrate the effectiveness of a counterintuitive targetless approach to training target detection in X-ray baggage search, based on basic principles of distractor suppression and rejection, with potential for use as a real-world training tool

High-pressure photoacoustic calorimetry

A high-pressure photoacoustic calorimeter has been developed to operate up to 200 MPa. Photoacoustic calorimetry can be used to study the microsecond kinetics and thermodynamics of reactions in solution. Both thermal expansion and volume of reaction contribute to the generation of the photoacoustic signal, and the separation of these contributions has been achieved by the variation of pressure. The construction of a stainless-steel flow cell, bellows, and a high-pressure manifold are described. These components enable rapid sample change and sample flow at high pressure. As a test, the enthalpy and volume of reaction were determined for diphenylcyclopropenone decomposition to diphenylethyne and carbon monoxide. © 2000 American Institute of Physics