Robust Parameter Selection for Parallel Tempering

This paper describes an algorithm for selecting parameter values (e.g. temperature values) at which to measure equilibrium properties with Parallel Tempering Monte Carlo simulation. Simple approaches to choosing parameter values can lead to poor equilibration of the simulation, especially for Ising spin systems that undergo $1^st$-order phase transitions. However, starting from an initial set of parameter values, the careful, iterative respacing of these values based on results with the previous set of values greatly improves equilibration. Example spin systems presented here appear in the context of Quantum Monte Carlo.Comment: Accepted in International Journal of Modern Physics C 2010, http://www.worldscinet.com/ijmp

Delivery of human apolipoprotein (apo) E to liver by an [E1(-), E3(-), polymerase(-), pTP(-)] adenovirus vector containing a liver-specific promoter inhibits atherogenesis in immunocompetent apoE-deficient mice

Recombinant adenovirus (rAd)-mediated apoE gene transfer to the liver of apoE(-/-) mice is anti-atherogenic. However, first generation rAd vectors were associated with immune clearance of transduced hepatocytes, while an improved [E1(-), E3(-) polymerase(-)] adenovirus vector that persisted in the liver, had transient effects due to cellular shutdown of the cytomegalovirus (CMV) promoter (Ad-CMV-apoE). Here, we utilise an improved class of rAd vector with multiple deletions in the E1, E3, polymerase and pTP (pre-terminal protein) genes, which contains a modular synthetic liver-specific promoter (LSP) to drive expression of the human apoE cDNA (Ad-LSP-apoE) for hepatic gene transfer. Approximately 1 year old apoE(-/-) mice were injected intravenously with 4x10(10) virus particles of either Ad-LSP-apoE or Ad-CMV-apoE. Animals were monitored for plasma apoE, total plasma cholesterol and plasma lipoprotein distribution. The effect of Ad-LSP-apoE on atheroma progression was assessed in animals killed at 8 and 28 weeks after the injections. Ad-LSP-apoE vector administration gave sustained, though low, levels of plasma apoE throughout the study period without inducing a humoral immune response, but failed to reduce plasma cholesterol or normalize the adverse lipoprotein profile. Animals killed 8 weeks after the injections, demonstrated no significant retardation of atherosclerosis, whereas aortic lesions in those killed at 28 weeks were significantly reduced by 30% ( P< 0.006) compared to untreated animals. In summary, the combination of a multiply deleted rAd vector with a liver-specific promoter provided sustained low levels of plasma apoE, resulting in significant retardation of aortic atherosclerotic lesions

Leaf Development of Rurnex patientia L. Exposed to UV Irradiation (280-320 nm)

Two factors which affect leaf ontogeny and ultimate leaf size: (1) the rate and duration of cell expansion, and (2) the rate and duration of cell division, were examined for their role in the slowed early growth rate and smaller ultimate leaf size when plants are exposed to ultraviolet-B (UV-B) radiation. Rumex patientia L. was grown in controlled environment chambers under enhanced UV-B radiation (equivalent to daily solar UV-B irradiation at 40°N latitude in mid-May with an atmospheric ozone concentration of 0.20 atm-cm) and control treatments. The pattern of growth as expressed in changes of mean cell size of two distinct cell types, tissue cell density, and length of the entire blade are consistent with the hypothesis that the radiation primarily affects cell division rather than cell expansion. Furthermore, it appears that the radiation probably alters the rate rather than the duration of cell division. An understanding of the mechanism of radiation damage should facilitate prediction of how this stress may interact with other stresses to which plants are normally subjected

Shaping plasmon beams via the controlled illumination of finite-size plasmonic crystals

Plasmonic crystals provide many passive and active optical functionalities, including enhanced sensing, optical nonlinearities, light extraction from LEDs and coupling to and from subwavelength waveguides. Here we study, both experimentally and numerically, the coherent control of SPP beam excitation in finite size plasmonic crystals under focussed illumination. The correct combination of the illuminating spot size, its position relative to the plasmonic crystal, wavelength and polarisation enables the efficient shaping and directionality of SPP beam launching. We show that under strongly focussed illumination, the illuminated part of the crystal acts as an antenna, launching surface plasmon waves which are subsequently filtered by the surrounding periodic lattice. Changing the illumination conditions provides rich opportunities to engineer the SPP emission pattern. This offers an alternative technique to actively modulate and control plasmonic signals, either via micro- and nano-electromechanical switches or with electro- and all-optical beam steering which have direct implications for the development of new integrated nanophotonic devices, such as plasmonic couplers and switches and on-chip signal demultiplexing. This approach can be generalised to all kinds of surface waves, either for the coupling and discrimination of light in planar dielectric waveguides or the generation and control of non-diffractive SPP beams