Steven Johnston

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A quantum mechanical description of particle propagation on the discrete spacetime of a causal set is presented. The model involves a discrete path integral in which trajectories within the causal set are summed over to obtain a particle propagator. The sum-over-trajectories is achieved by a matrix geometric series. For causal sets generated by sprinkling(More)
In this paper we present the features of a new physical device prototyping platform called Microsoft .NET Gadgeteer along with our initial experiences using it to teach computer science in high schools. Gadgeteer makes it easy for newcomers to electronics and computing to plug together modules with varied functionality and to program the resulting system's(More)
Dilute nitride films with a roughly 1 eV band gap can be lattice-matched to gallium arsenide and germanium, and therefore could become a critical component in next-generation multijunction solar cells. To date most dilute nitride solar cells have been plagued with poor efficiency, due in large part to short diffusion lengths. This study focuses on two(More)
Thin-film CdS is used as a window layer in most of the current thin-film polycrystalline device technologies including absorbers based on cadmium telluride (CdTe) and copper indium selenide (CIS) and copper indium gallium se-lenide (CIGS). Device performance has been linked to the deposition technique and posttreatment of the CdS layer. Here we used the(More)
Contactless measurement of important semiconductor parameters has become a popular trend of current semiconductor technology. Here we will describe an improved version of radio frequency photoconductive decay (RFPCD) operating in the ultra-high frequency (UHF) region. This work will show that the improved technique is capable of measuring samples ranging in(More)
Science, technology, networks and society are subjects of critical communication inquiry. Biopolitics focuses on power relationships in communicative assemblages and operations in the areas of health, medicine, environment, and security. This class identifies studies of communication controversies over research, development, dissemination and circulation of(More)
Purpose: Novel oral antiplatelet (NOAP) (prasugrel and ticagrelor) and direct oral anticoagulant drugs (DOAC) (dabigatran, rivaroxaban and apixaban) have emerged in the last decade. This study was undertaken to determine current approaches taken to the management of patients taking these agents in dental practice in a remote and rural setting. Methods: A(More)