Given a chromosome represented by a permutation of genes, a block-interchanges is proposed as a generalized transposition that affects a chromosome by swapping two nonintersecting segments of genes. The problem of sorting by block-interchanges is to find a minimum series of block-interchanges for transforming one chromosome into another. In this paper, we present an O(n+ δ log n) time algorithm...

The question of whether interchanges of spatially neighboring residues are coupled, or whether they change independently of each other, has been addressed repeatedly over the last few years. Utilizing a residue order-independent structural comparison tool, we investigated interchanges of spatially adjacent residue pairs in conserved 3D environments in globally dissimilar protein structures. We ...

An efficient freeway system will be essential to the development of Africa, and interchanges are a key to that efficiency. Around the world, many interchanges between freeways and surface streets, called service interchanges, are of the diamond configuration, and interchanges using roundabouts or loop ramps are also popular. However, many diamond interchanges have serious operational problems, ...

Let D be a statistical design consisting of v varieties on b blocks. We say it is binary if a variety occurs at most once on every block. For varieties p and q on blocks x and y respectively, we can obtain design D' from D by interchanging p and q (so p is on y and q is on x). We say that the exchange is binary if either x y, or p q, or: q not on x and p not on y. If D is binary then D' is also...