Leonard Cockayne: Horticulturist

Foreword Leonard

Much has changed in computer security since 1973, when the Bell-LaPadula model was first published. Development has moved away from kernel-based secure systems toward application-level security capabilities, providing secure transactions on top of commercial, nonsecure operating systems. The potential for widespread use of encryption for privacy, authentication, and other services, as embodied ...

Leonard Colebrook (1883?1967)

Leonard Colebrook was a physician who researched bacteria and infections in England during the twentieth century. In 1936, Colebrook deployed the antibiotic Prontosil to treat puerperal fever, a disorder that results from bacterial infections in the uterine tracts of women after childbirth or abortions. Colebrook also advanced care for burn patients by advocating for the creation of burn units ...

OBITUARY : Joseph Leonard

Joseph Leonard Doob was born in Cincinnati, Ohio, USA on 27 February 1910. In an interview Joe gave for Statistical Science (see Snell (1997)), he said that in grammar school he built a crystal set and in high school operated a radio transmitter. This led him to think he would major in mathematical physics when he entered Harvard in 1926. However, after taking two physics courses, Doob decided ...

Leonard Colebrook, 1883-1967.

Balanced Leonard Pairs

Let K denote a field, and let V denote a vector space over K with finite positive dimension. By a Leonard pair on V we mean an ordered pair of linear transformations A : V → V and A∗ : V → V that satisfy the following two conditions: (i) There exists a basis for V with respect to which the matrix representing A is irreducible tridiagonal and the matrix representing A∗ is diagonal. (ii) There ex...