A critical success factor for the reuse of learning objects is the ease by which they may be repurposed in order to enable reusability in a different teaching context from which they were originally designed. The current generation of tools for creating, storing, describing and locating learning objects are best suited for users with technical expertise. Such tools are an obstacle to teachers w...

  Objective(s): Adeno-associated virus type 2 (AAV2) vectors are widely used for both experimental and clinical gene therapy. A recent research has shown that the performance of these vectors can be greatly improved by substitution of specific surface-exposed tyrosine residues with phenylalanines. In this study, a fast and simple method is presented to generate AAV2 vector helper plasmids encod...

New opportunities for the refinement of ionospheric modelling and reduction of the ionospheric error in GPS measurements arise since a third-frequency will be introduced for the modernised GPS system. This paper investigates theoretical models of the ionospheric refractive error. A triple-frequency method of correcting the 1 and 2 order ionospheric refraction is presented and a triple-frequency...

A set of agricultural suppliers with low demands can save on long-haul transportation costs by consolidating their product. We consider a system with stochastic demand and a single consolidation point near the suppliers. We propose a look-ahead heuristic that takes advantage of economies of scale by aiming to ship larger quantities. We experimentally compare the heuristic's performance against ...

We extend the logic and semantics of authorization due to Abadi, Lampson, et al. to support restricted delegation. Our formal model provides a simple interpretation for the variety of constructs in the Simple Public Key Infrastructure (SPKI), and lends intuition about possible extensions. We discuss both extensions that our semantics supports and extensions that it cautions against.

Abstract: Dozens of markets of all types are in the early stages of a revolution as the Internet and related technologies vastly expand the variety of products that can be produced, promoted and purchased. Although this revolution is based on a simple set of economic and technological drivers, the authors argue that its implications are far-reaching for managers, consumers and the economy as a ...