Do the gravitational corrections to the beta functions of the quartic and Yukawa couplings have an intrinsic physical meaning?

We study the beta functions of the quartic and Yukawa couplings of General Relativity and Unimodular Gravity coupled to the $\lambda\phi^4$ and Yukawa theories with masses. We show that the General Relativity corrections to those beta functions as obtained from the 1PI functional by using the standard MS multiplicative renormalization scheme of Dimensional Regularization are gauge dependent and, further, that they can be removed by a non-multiplicative, though local, field redefinition. An analogous analysis is carried out when General Relativity is replaced with Unimodular Gravity. Thus we show that any claim made about the change in the asymptotic behaviour of the quartic and Yukawa couplings made by General Relativity and Unimodular Gravity lack intrinsic physical meaning.Comment: 6 pages, 7 figure

Organic plant breeding

This report was presented at the UK Organic Research 2002 Conference. To a major extent, organic farming depends currently on plant and animal varieties that have been bred for non-organic farming and that are often not suited to organic production. This position is inconsistent with a holistic approach to organic agriculture. Organically-bred plant varieties are needed to develop both the potential of organic agriculture and its integrity. A first attempt at developing a concept for organic plant breeding methodology has been proposed. A novel approach to breeding for organic production has also been started. Further development needs a parallel approach to animal breeding for organic systems