Higher dimensional Automorphic Lie Algebras

The paper presents the complete classification of Automorphic Lie Algebras based on $\mathfrak{sl}_n (\mathbb{C})$, where the symmetry group $G$ is finite and the orbit is any of the exceptional $G$-orbits in $\overline{\mathbb{C}}$. A key feature of the classification is the study of the algebras in the context of classical invariant theory. This provides on one hand a powerful tool from the computational point of view, on the other it opens new questions from an algebraic perspective, which suggest further applications of these algebras, beyond the context of integrable systems. In particular, the research shows that Automorphic Lie Algebras associated to the $\mathbb{T}\mathbb{O}\mathbb{Y}$ groups (tetrahedral, octahedral and icosahedral groups) depend on the group through the automorphic functions only, thus they are group independent as Lie algebras. This can be established by defining a Chevalley normal form for these algebras, generalising this classical notion to the case of Lie algebras over a polynomial ring.Comment: 43 pages, standard LaTeX2

An analysis by metabolic labelling of the encephalomyocarditis virus ribosomal frameshifting efficiency and stimulators

Programmed −1 ribosomal frameshifting is a mechanism of gene expression whereby specific signals within messenger RNAs direct a proportion of ribosomes to shift −1 nt and continue translating in the new reading frame. Such frameshifting normally depends on an RNA structure stimulator 3$^\prime$-adjacent to a ‘slippery’ heptanucleotide shift site sequence. Recently we identified an unusual frameshifting mechanism in encephalomyocarditis virus, where the stimulator involves a $\textit{trans}$-acting virus protein. Thus, in contrast to other examples of −1 frameshifting, the efficiency of frameshifting in encephalomyocarditis virus is best studied in the context of virus infection. Here we use metabolic labelling to analyse the frameshifting efficiency of wild-type and mutant viruses. Confirming previous results, frameshifting depends on a G_GUU_UUU shift site sequence and a 3$^\prime$-adjacent stem-loop structure, but is not appreciably affected by the ‘StopGo’ sequence present ~30 nt upstream. At late timepoints, frameshifting was estimated to be 46–76 % efficient.Wellcome Trust [088789, 106207], UK Biotechnology and Biological Research Council (BBSRC) [BB/J007072/1], European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme [grant agreement No (646891)]

Kac--Moody groups and automorphic forms in low dimensional supergravity theories

Kac--Moody groups $G$ over $\mathbb{R}$ have been conjectured to occur as symmetry groups of supergravity theories dimensionally reduced to dimensions less than 3, and their integral forms $G(\mathbb{Z})$ conjecturally encode quantized symmetries. In this review paper, we briefly introduce the conjectural symmetries of Kac--Moody groups in supergravity as well as the known evidence for these conjectures. We describe constructions of Kac--Moody groups over $\R$ and $\Z$ using certain choices of fundamental modules that are considered to have physical relevance. Eisenstein series on certain finite dimensional algebraic groups are known to encode quantum corrections in the low energy limit of superstring theories. We describe briefly how the construction of Eisenstein series extends to Kac--Moody groups. The constant terms of Eisenstein series on $E_9$, $E_{10}$ and $E_{11}$ are predicted to encode perturbative string theory corrections.Comment: arXiv admin note: text overlap with arXiv:1308.619

Testing performance of standards-based protocols in DPM

In the interests of the promotion of the increased use of non-proprietary protocols in grid storage systems, we perform tests on the performance of WebDAV and pNFS transport with the DPM storage solution. We find that the standards-based protocols behave similarly to the proprietary standards currently in use, despite encountering some issues with the state of the implementation itself. We thus conclude that there is no performance-based reason to avoid using such protocols for data management in future