Aplanochytrium kerguelensis gen. nov. spec. nov., a new phycomycete from subantarctic marine waters

A new monocentric marine fungus, Aplanochytrium kerguelensis gen. nov. spec. nov., was recovered from water samples taken in the vicinity of the Kerguelen Islands in the South Indian Ocean during a cruise of the research vessel USNS “Eltanin”. Aplanochytrium is very similar to Thraustochytrium Sparrow (1936) in having a chytrid-like thallus and in being able to utilize pine pollen as a substrate to which it establishes contact by well-developed rhizoids. At maturity, however, only aplanospores are formed, as in Dermocystidium sensu Goldstein and Moriber (1966).Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46151/1/203_2004_Article_BF00715023.pd

Helicity-dependent cross sections for the photoproduction of π0\pi^0 pairs from nucleons

The double-polarization observable $E$ and helicity-dependent cross sections $\sigma_{1/2}$, $\sigma_{3/2}$ have been measured for the photoproduction of $\pi^0$ pairs off quasi-free protons and neutrons at the Mainz MAMI accelerator with the Crystal Ball/TAPS setup. A circularly polarized photon beam was produced by bremsstrahlung from longitudinally polarized electrons and impinged on a longitudinally polarized deuterated butanol target. The reaction products were detected with an almost $4\pi$ covering calorimeter. The results reveal for the first time the helicity- and isospin-dependent structure of the $\gamma N\rightarrow N\pi^0\pi^0$ reaction. They are compared to predictions from reaction models in view of nucleon resonance contributions and also to a refit of one model that predicted results for the proton and for the neutron target. The comparison of the prediction and the refit demonstrate the large impact of the new data.Comment: Submitted to Phys. Rev. Let