Special Geometry and Automorphic Forms

We consider special geometry of the vector multiplet moduli space in compactifications of the heterotic string on $K3 \times T^2$ or the type IIA string on $K3$-fibered Calabi-Yau threefolds. In particular, we construct a modified dilaton that is invariant under $SO(2, n; Z)$ T-duality transformations at the non-perturbative level and regular everywhere on the moduli space. The invariant dilaton, together with a set of other coordinates that transform covariantly under $SO(2, n; Z)$, parameterize the moduli space. The construction involves a meromorphic automorphic function of $SO(2, n; Z)$, that also depends on the invariant dilaton. In the weak coupling limit, the divisor of this automorphic form is an integer linear combination of the rational quadratic divisors where the gauge symmetry is enhanced classically. We also show how the non-perturbative prepotential can be expressed in terms of meromorphic automorphic forms, by expanding a T-duality invariant quantity both in terms of the standard special coordinates and in terms of the invariant dilaton and the covariant coordinates.Comment: 21 pages, plain LaTeX. Minor changes, references adde

Mosaic origin of the mitochondrial proteome.

Item does not contain fulltextAlthough the origin of mitochondria from the endosymbiosis of an alpha-proteobacterium is well established, the nature of the host cell, the metabolic complexity of the endosymbiont and the subsequent evolution of the proto-mitochondrion into all its current appearances are still the subject of discovery and sometimes debate. Here we review what has been inferred about the original composition and subsequent evolution of the mitochondrial proteome and essential mitochondrial systems. The evolutionary mosaic that currently constitutes mitochondrial proteomes contains (i) endosymbiotic proteins (15-45%), (ii) proteins without detectable orthologs outside the eukaryotic lineage (40%), and (iii) proteins that are derived from non-proteobacterial Bacteria, Bacteriophages and Archaea (15%, specifically multiple tRNA-modification proteins). Protein complexes are of endosymbiotic origin, but have greatly expanded with novel eukaryotic proteins; in contrast to mitochondrial enzymes that are both of proteobacterial and non-proteobacterial origin. This disparity is consistent with the complexity hypothesis, which argues that proteins that are a part of large, multi-subunit complexes are unlikely to undergo horizontal gene transfer. We observe that they neither change their subcellular compartments in the course of evolution, even when their genes do.1 november 201

Care in Europe after presenting to the emergency department with a seizure; position paper and insights from the European Audit of Seizure Management in Hospitals

info:eu-repo/semantics/publishe