We give a new infinite family of group homomorphisms from the braid group Bk to the symmetric group Smk for all k and m ≥ 2. Most known permutation representations of braids are included in this family. We prove that the homomorphisms in this family are non-cyclic and transitive. For any divisor l of m, 1 ≤ l < m, we prove in particular that if m l is odd then there are 1+ m l non-conjugate hom...

BACKGROUND In the Netherlands about 50% of whole blood donors return to give blood after an invitation to donate. This study aimed to investigate the characteristics of donor return behaviour and to gain insight into the barriers to blood donation reported by the donors themselves. MATERIALS AND METHODS A total of 4,901 whole blood donors were invited to donate in week 39 of 2009. Barriers me...

Separating what is relevant from what is not can turn an intractable learning problem into a solvable one by reducing the complexity of the problem. Abstraction is a good general tool for sorting out relevant and irrelevant information. There are two common types of abstraction: state abstraction, and hierarchical actions. This paper examines the ways in which state abstraction can be used in t...

147 A pproximately one third of all children with seizure disorders are not controlled with standard antiepileptic therapy. A high proportion of these intractable cases are associated with lesions acquired prenatally. Indeed, developmental lesions account for about 85% of the preadolescent surgical caseload for epilepsy. This article will review the most common types of developmental lesions as...

At CRYPTO 2014, Abe, Groth, Ohkubo and Tibouchi presented genericsigner structure-preserving signature schemes using Type 2 pairings. The schemes were claimed to enjoy the smallest number of group elements in signatures and the fastest signature verification. By properly accounting for the concrete structure of the underlying group and subgroup membership testing of group elements in signatures...

A modification of the popular unification model for Seyfert galaxies is proposed, which takes into account recent observational findings on the statistical properties of both type 1 and type 2 Seyferts. In the proposed scenario, Compton–thick Seyfert 2 galaxies are those sources observed through compact, thick matter (the ‘torus’), while Compton–thin/ intermediate Seyfert galaxies are obscured ...

This paper discusses the types of undercover investigations conducted on the Internet. Computer-assisted telephone interviews were conducted with police about 544 undercover cases ending in arrest for an Internet-related sex crime against a minor in 2006. The two most common types of undercover investigations involved police posing online as minors (76%) and undercover police investigations of ...