Search for flavor-changing neutral currents and lepton-family-number violation in two-body D0 decays

Results of a search for the three neutral charm decays, D0 -> mu e, D0 -> mu mu, and D0 -> e e, are presented. This study was based on data collected in Experiment 789 at the Fermi National Accelerator Laboratory using 800 GeV/c proton-Au and proton-Be interactions. No evidence is found for any of the decays. Upper limits on the branching ratios, at the 90% confidence level, are obtained.Comment: 28 pages, 18 figures. Submitted to Physical Review

Preliminary results from Fermilab E789

Fermilab experiment 789 studies low-multiplicity decays of neutral D and B mesons in a high-rate fixed-target environment. Preliminary results from the 1991 run are presented

Occurence of Verticillium dahliae on sunflower (Helianthus annus ) in the UK

In August 1994 verticilliosis-like symptoms were noticed in a maturing crop of sunflower at IACR-Rothamsted. Wilting plants with chlorotic areas on some leaves, and dark areas of microsclerotia at the base of stems, were first observed on 11 August. As the plants matured, dark stripes were also observed on the stems. Many stems became brittle and later collapsed. Infected xylem showed a brown discolouration, later turning to black, and microsclerotia developed. Verticillium dahliae was isolated from an parts of the plant. In general, once symptoms were present, the incidence of verticilliosis-affected plants increased, and the disease developed, more rapidly in early maturing varieties than in the later maturing types. At harvest, incidence ranged between 24.5% and 89.8%, depending on variety. Early maturing varieties appeared to be more susceptible than later maturing types. Isolates of V. dahliae were cultured in the laboratory. Sunflower plants were artificially inoculated with these isolates and developed verticilliosis symptoms when grown under controlled environmental conditions