Expression of chloramphenicol acetyltransferase in Bacillus subtilis under the control of a phytoplasma promoter

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Onset of Superfluidity in 4He Films Adsorbed on Disordered Substrates

We have studied 4He films adsorbed in two porous glasses, aerogel and Vycor, using high precision torsional oscillator and DC calorimetry techniques. Our investigation focused on the onset of superfluidity at low temperatures as the 4He coverage is increased. Torsional oscillator measurements of the 4He-aerogel system were used to determine the superfluid density of films with transition temperatures as low as 20 mK. Heat capacity measurements of the 4He-Vycor system probed the excitation spectrum of both non-superfluid and superfluid films for temperatures down to 10 mK. Both sets of measurements suggest that the critical coverage for the onset of superfluidity corresponds to a mobility edge in the chemical potential, so that the onset transition is the bosonic analog of a superconductor-insulator transition. The superfluid density measurements, however, are not in agreement with the scaling theory of an onset transition from a gapless, Bose glass phase to a superfluid. The heat capacity measurements show that the non-superfluid phase is better characterized as an insulator with a gap.Comment: 15 pages (RevTex), 21 figures (postscript

Advanced application of flexible metamaterials at visible frequencies

The authors acknowledge support by EPSRC (EP/I004602/1 and EP/J004200/1).Flexible metamaterials (FMMs) at optical frequencies can conform to a wide range of target geometries whilst allowing their optical properties to be tuned post-fabrication. Here we discuss this potential by presenting our recent and preliminary results, obtained for FMMs at visible frequencies for sensing, filtering and imaging applications.Publisher PD

Economic impact of pome and stone fruit phytoplasmas

International audienc