Log-Poisson statistics and full aging in glassy systems

We argue that Poisson statistics in logarithmic time provides an idealized description of non-equilibrium configurational rearrangements in aging glassy systems. The description puts stringent requirements on the geometry of the metastable attractors visited at age $t_w$. Analytical implications for the residence time distributions as a function of $t_w$ and the correlation functions are derived. These are verified by extensive numerical studies of short range Ising spin glasses.Comment: v3 (final): 8 pages, 4 figures. Minor change

Faster Monte Carlo Simulations at Low Temperatures. The Waiting Time Method

We discuss a rejectionless global optimization technique which, while being technically similar to the recently introduced method of Extremal Optimization, still relies on a physical analogy with a thermalizing system. Our waiting time method (WTM) is mathematically equivalent to the usual Metropolis algorithm, but considerably more efficient at low temperatures. The WTM can be used at constant temperature or it can be combined with annealing techniques. It is especially well suited for studying the low temperature relaxation of complex systems as glasses and spin glasses. In the paper we describe the method and test it on a spin glass example by comparing its performance to Extremal Optimization.Comment: 14 pages, 5 figures, LaTe

In vivo screening of modified siRNAs for non-specific antiviral effect in a small fish model: number and localization in the strands are important

Small interfering RNAs (siRNAs) are promising new active compounds in gene medicine but the induction of non-specific immune responses following their delivery continues to be a serious problem. With the purpose of avoiding such effects chemically modified siRNAs are tested in screening assay but often only examining the expression of specific immunologically relevant genes in selected cell populations typically blood cells from treated animals or humans. Assays using a relevant physiological state in biological models as read-out are not common. Here we use a fish model where the innate antiviral effect of siRNAs is functionally monitored as reduced mortality in challenge studies involving an interferon sensitive virus. Modifications with locked nucleic acid (LNA), altritol nucleic acid (ANA) and hexitol nucleic acid (HNA) reduced the antiviral protection in this model indicative of altered immunogenicity. For LNA modified siRNAs, the number and localization of modifications in the single strands was found to be important and a correlation between antiviral protection and the thermal stability of siRNAs was found. The previously published sisiRNA will in some sequences, but not all, increase the antiviral effect of siRNAs. The applied fish model represents a potent tool for conducting fast but statistically and scientifically relevant evaluations of chemically optimized siRNAs with respect to non-specific antiviral effects in vivo