Lattice QED and Universality of the Axial Anomaly

We give a perturbative proof that U(1) lattice gauge theories generate the axial anomaly in the continuum limit under very general conditions on the lattice Dirac operator. These conditions are locality, gauge covariance and the absense of species doubling. They hold for Wilson fermions as well as for realizations of the Dirac operator that satisfy the Ginsparg-Wilson relation. The proof is based on the lattice power counting theorem. The results generalize to non-abelian gauge theories.Comment: LATTICE99(theoretical developments) 3 page

Quantitative relationships in the infection cycle of seed-borne net blotch

Seed-borne net blotch is a threat to organic barley seed production in Denmark because it often exceeds the recommended 15% contamination threshold in barley seed lots. This threatens the supply of organic barley growers with organically produced healthy barley seeds. The ORGSEED project aims at quantifying the links between initial seed contamination, primary seedling infection, disease severity during the growing season, yield parameters and new contamination of the harvested grains to improve decision support for handling net blotch contaminations in organic barley- and barley seed production. The harvested grains of spring barley varieties grown at several sites in Denmark in 2002 and 2003 were used as seed lots in subsequent trials in 2003 and 2004. The seed lots covered a range of contamination levels of seed-borne net blotch for each variety. Net blotch contamination level, 1000 grain weight and germination ability of the grains were determined and net blotch development during the growing season was visually assessed. The net blotch contamination level of harvested grains was highly positively correlated with net blotch severity at growth stage 70 (beginning of grain filling, gs 70). A general linear model explained 72% of the variation of grain infection based on effects of [variety x year] and [variety x year x net blotch severity at gs 70]. Net blotch severity at gs 70 was highly positively correlated with the net blotch contamination level of the seeds and a general linear model explained 71% of the variation of net blotch severity at gs 70 based on effects of variety and seed contamination level. The results indicate that the transmission efficiency of net blotch from the epidemic on the foliage to the grains differs among varieties and that the effects of seed contamination on net blotch development later during the season may be variety-specific as well. Net blotch disease severity was highly negatively correlated with 1000 grain weight and explained, together with [site x year] effects, 58% of its variation. Our results underline the importance of varietal resistance for seed health and suggest that the level of varietal resistance be included in considerations concerning the establishment of seed contamination thresholds

Effect of production system and geographic location on milk quality parameters

A main reason for the rapid increase in organic food consumption is the perception that organic foods have a superior nutritional composition and/or convey health benefits. However, there is currently limited scientific knowledge about the effect of production systems on food composition. The study reported here compared fatty acid profiles and levels of fat soluble antioxidants in milk from organic and conventional production systems in 5 geographic regions in Europe (Wales, England, Denmark, Sweden and Italy). Levels of nutritionally desirable mono- and poly-unsaturated fatty acids (vaccenic acid, CLA, α-linolenic acid) and/or a range of fat soluble antioxidants were found to be significantly higher in organic milk

An extendable modular endoprosthetic system for bone tumour management in the leg

A modular endoprosthetic system has been developed at the Groningen University Hospital and the University of Twente. The system can bridge a defect resulting from the resection of a malignant bone tumour which has developed around the knee joint of a child. Since the other healthy leg continues to grow, the system includes an element whose length can be adjusted non-invasively by using an external magnetic field. In addition to this lengthening element, there are one hip and two knee components, connectors of various lengths, and fixation elements. The paper describes the elements of the modular endoprosthetic system. Tables are created by means of which the elemental composition of such an endoprosthesis can be determined for each individual patient

Renormalization of lattice gauge theories with massless Ginsparg Wilson fermions

Using functional techniques, we prove, to all orders of perturbation theory, that lattice vector gauge theories with Ginsparg Wilson fermions are renormalizable. For two or more massless fermions, they satisfy a flavour mixing axial vector Ward identity. It involves a lattice specific part that is quadratic in the vertex functional and classically irrelevant. We show that it stays irrelevant under renormalization. This means that in the continuum limit the (standard) chiral symmetry becomes restored. In particular, the flavour mixing current does not require renormalization.Comment: 13 pages, Latex2

Udsædsbårne sygdomme i økologisk såsæd - betydning og skadetærskler

Det økologiske projekt ORGSEED har givet ny viden om skadetærsklerne for de vigtigste udsædsbårne sygdomme i korn og ærter. I projektets sidste del vil disse tærskelværdier blive vurderet med henblik på justering. Sammenholdt med nye metoder til bestemmelse af den faktiske forekomst af udsædsbårne sygdomme, vil det give en mere sikker karakterisering af den økologiske såsæd og hermed mindre unødig kassation

Efficient scheme for one-way quantum computing in thermal cavities

We propose a practical scheme for one-way quantum computing based on efficient generation of 2D cluster state in thermal cavities. We achieve a controlled-phase gate that is neither sensitive to cavity decay nor to thermal field by adding a strong classical field to the two-level atoms. We show that a 2D cluster state can be generated directly by making every two atoms collide in an array of cavities, with numerically calculated parameters and appropriate operation sequence that can be easily achieved in practical Cavity QED experiments. Based on a generated cluster state in Box$^{(4)}$ configuration, we then implement Grover's search algorithm for four database elements in a very simple way as an example of one-way quantum computing.Comment: 6 pages, 3 figure

Topological order in 1D Cluster state protected by symmetry

We demonstrate how to construct the Z2*Z2 global symmetry which protects the ground state degeneracy of cluster states for open boundary conditions. Such a degeneracy ultimately arises because the set of stabilizers do not span a complete set of integrals of motion of the cluster state Hamiltonian for open boundary conditions. By applying control phase transformations, our construction makes the stabilizers into the Pauli operators spanning the qubit Hilbert space from which the degeneracy comes.Comment: 1 figure, To be published in Quantum Information Processin