4,063 research outputs found
S-adenosyl-l-methionine: (S) -7,8,13, 14-tetrahydroberberine--n-methyltransferase, a branch point enzyme in the biosynthesis of benzophenanthridine and protopine alkaloids.
Get PDFThe enzyme which transfers the CH3-group of S-adenosylmethionine to the nitrogen atom of (S)-tetrahydroberberine and (S)-stylopine is found to occur in a number of plant cell cultures originating from species containing alkaloids; it is located at an important branch point in isoquinoline alkaloid biosynthesis
The concept of religion in Meiji popular discourse: An analysis of the newspaper Yomiuri Shimbun
Get PDFQuasiparticle Self-Consistent GW Theory
Full text linkIn past decades the scientific community has been looking for a reliable
first-principles method to predict the electronic structure of solids with high
accuracy. Here we present an approach which we call the quasiparticle
self-consistent GW approximation (QpscGW). It is based on a kind of
self-consistent perturbation theory, where the self-consistency is constructed
to minimize the perturbation. We apply it to selections from different classes
of materials, including alkali metals, semiconductors, wide band gap
insulators, transition metals, transition metal oxides, magnetic insulators,
and rare earth compounds. Apart some mild exceptions, the properties are very
well described, particularly in weakly correlated cases. Self-consistency
dramatically improves agreement with experiment, and is sometimes essential.
Discrepancies with experiment are systematic, and can be explained in terms of
approximations made.Comment: 12 pages, 3 figure
Maxwell stress in fluid mixtures
Full text linkWe examine the structure of Maxwell stress in binary fluid mixtures under an
external electric field and discuss its consequence. In particular, we show
that, in immiscible blends, it is intimately related to the statistics of
domain structure. This leads to a compact formula, which may be useful in the
investigation of electro-rheological effects in such systems. The stress tensor
calculated in a phase separated fluid under a steady electric field is in a
good agreement with recent experiments.Comment: 5 page
Many-body Electronic Structure of Metallic alpha-Uranium
Full text linkWe present results for the electronic structure of alpha uranium using a
recently developed quasiparticle self-consistent GW method (QSGW). This is the
first time that the f-orbital electron-electron interactions in an actinide has
been treated by a first-principles method beyond the level of the generalized
gradient approximation (GGA) to the local density approximation (LDA). We show
that the QSGW approximation predicts an f-level shift upwards of about 0.5 eV
with respect to the other metallic s-d states and that there is a significant
f-band narrowing when compared to LDA band-structure results. Nonetheless,
because of the overall low f-electron occupation number in uranium,
ground-state properties and the occupied band structure around the Fermi energy
is not significantly affected. The correlations predominate in the unoccupied
part of the f states. This provides the first formal justification for the
success of LDA and GGA calculations in describing the ground-state properties
of this material.Comment: 4 pages, 3 fihgure
Notes on the Hamiltonian formulation of 3D Yang-Mills theory
Full text linkThree-dimensional Yang-Mills theory is investigated in the Hamiltonian
formalism based on the Karabali-Nair variable. A new algorithm is developed to
obtain the renormalized Hamiltonian by identifying local counterterms in
Lagrangian with the use of fictitious holomorphic symmetry existing in the
framework with the KN variable. Our algorithm is totally algebraic and enables
one to calculate the ground state wave functional recursively in gauge
potentials. In particular, the Gaussian part thus calculated is shown to
coincide with that obtained by Leigh et al. Higher-order corrections to the
Gaussian part are also discussed.Comment: 26 pages, LaTeX; discussions on IR regulators and local counterterms
improved, references adde
Adequacy of Approximations in GW Theory
Full text linkWe use an all-electron implementation of the GW approximation to analyze
several possible sources of error in the theory and its implementation. Among
these are convergence in the polarization and Green's functions, the dependence
of QP levels on choice of basis sets, and differing approximations for dealing
with core levels. In all GW calculations presented here, G and W are generated
from the local-density approximation (LDA), which we denote as the \GLDA\WLDA
approximation. To test its range of validity, the \GLDA\WLDA approximation is
applied to a variety of materials systems. We show that for simple sp
semiconductors, \GLDA\WLDA always underestimates bandgaps; however, better
agreement with experiment is obtained when the self-energy is not renormalized,
and we propose a justification for it. Some calculations for Si are compared to
pseudopotential-based \GLDA\WLDA calculations, and some aspects of the
suitability of pseudopotentials for GW calculations are discussed.Comment: 38 pages,6 figures. Minor Revision
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