Accessibility and usability guidelines are available to design web sites accessible to blind users. However, the actual usability of accessible web pages varies depending on the type of information the user is dealing with. Museum web sites, including specimens and hall descriptions, need specific requirements to allow vision-impaired users, who navigate using a screenreader, to access pieces o...

We study the long-run stability of trade networks in a two-sided economy of agents labelled men and women. Each agent desires relationships with the other type, but having multiple partners is costly. This cost-benefit trade-off results in each agent having a single-peaked utility over the number of partners—the volume of trade—, the peak being greater for men than for women. We propose a stoch...

We prove a new combinatorial characterization of polynomial learnability from equiva lence queries and state some of its consequences relating the learnability of a class with the learnability via equivalence and membership queries of its subclasses obtained by restricting the instance space Then we propose and study two models of query learning in which there is a probability distribution on t...

This paper proposes a holistic lexicon-reduction method for ancient and modern handwritten Arabic documents. The word shape is represented by the weighted topological signature vector (W-TSV), which encodes graph data into a low-dimensional vector space. Three directed acyclic graph (DAG) representations are proposed for Arabic word shapes, based on topological and geometrical features. Lexicon...

There are two molecular machineries for pre-mRNA splicing-the major spliceosome and the minor spliceosome. In this issue of Cell, König et al. (2007) demonstrate that the two splicing pathways are spatially separated in the cell and may have distinct functions.

Feedback effects from asset prices to firm cash flows have been empirically documented. This finding raises a question for asset pricing: How are asset prices determined if price affects fundamental value, which in turn affects price? In this environment, by buying assets that others are buying, investors ensure high future cash flows for the firm and subsequent high returns for themselves. Hen...