BACKGROUND On average, cognition declines with age but this average hides considerable variability, including the chance of improvement. Here, we investigate how exercise is associated with cognitive change and mortality in older people and, particularly, whether exercise might paradoxically increase the risk of dementia by allowing people to live longer. METHODS AND PRINCIPAL FINDINGS In the...

Partial collection replication improves performance and scalability of a large-scale distributed information retrieval system by distributing excessive workloads, reducing network latency, and restricting some searches to a small percentage of data. In this paper, we rst examine queries from real system logs and show that there is suucient query locality in real systems to justify partial colle...

Different constructions by Cooke, Harper and Zabrodsky and by Cohen and Neisendorfer produce torsion free finite p-local H-spaces of rank l < p−1. The first construction goes through when l = p− 1 and we show the second does as well. However, the space produced need not be an H-space. We give a criterion for when an H-space is obtained. In the special case of rank 2 mod-3 H-spaces, we also give...

The operators on Lp = Lp[0, 1], 1 ≤ p < ∞, which are not commutators are those of the form λI + S where λ , 0 and S belongs to the largest ideal in L(Lp). The proof involves new structural results for operators on Lp which are of independent interest.

objective (s): from a genetic point of view, epilepsy is a polygenic multifactorial syndrome. the scn1a and b genes belong to a family of genes that provide instructions for making sodium channels. understanding the relevance of scn1a and scn1b gene polymorphisms to plasma concentration of carbamazepine (cbz) and its active metabolite carbamazepine 10, 11 epoxide (cbze), may shed more light on ...