We show that there are long binary quasi-cyclic self-dual (either Type I or Type II) codes satisfying the Gilbert–Varshamov bound.

A compact model for MTJs incorporating temperature and voltage dependencies is presented. Written in Verilog-A, the model is intended to aid in the development of emerging spintronics circuits (i.e. STT-MRAM). Matching with detailed micromagnetic simulations and measurements from 65nm CoFeB/MgO/CoFeB MTJs is shown. Introduction Recent advances in MgO based magnetic tunnel junctions (MTJs) show ...

S ome vertebrates, such as fi sh, amphibians, and lizards, have the ability to replace lost limbs and regenerate organs. Regeneration requires the reactivation of signaling molecules that were used during embryonic development. Weidinger has spent his career so far studying aspects of zebrafish embryogenesis, including the role of Wnt signaling molecules (1, 2), and has more recently been inves...

LADIES AND GENTLEMEN,-For upwards of forty years I have lived the busy life of a general practitioner attached to a small hospital in a provincial town. This demanded all my attention and most of my energies, but somehow within the last few years, I have been pitchforked into the arena of medical politics, and in that field great honours have been bestowed upon me. The very greatest of these -t...

We show that every self-orthogonal code over $\mathbb F_q$ of length $n$ can be extended to a self-dual code, if there exists self-dual codes of length $n$. Using a family of Galois towers of algebraic function fields we show that over any nonprime field $\mathbb F_q$, with $q\geq 64$, except possibly $q=125$, there are self-dual codes better than the asymptotic Gilbert--Varshamov bound.

We derive an isoperimetric theorem for sequences genenerated by feedback and consider block codes for the binary broadcast channel with two receivers and noiseless feedback. We get an outer bound by applying the isoperimetric theorem on the achievable rates for special cases of these codes with unequal error protection. We get a lower bound with a generalized Varshamov-Gilbert construction.

Self-dual double circulant codes of odd dimension are shown to be dihedral in even characteristic and consta-dihedral in odd characteristic. Exact counting formulae are derived for them and used to show they contain families of codes with relative distance satisfying a modified Gilbert-Varshamov bound.