Search results for "Sigma"
showing 10 items of 346 documents
Transcriptional regulation of theNε-fructoselysine metabolism inEscherichia coliby global and substrate-specific cues
2020
AbstractThermally processed food is an important part of the human diet. Heat-treatment, however, promotes the formation of so-called Amadori rearrangement products (ARPs), such as fructoselysine. The gut microbiota includingEscherichia colican utilize these compounds as a nutrient source. While the degradation route for fructoselysine is well described, regulation of the corresponding pathway genesfrlABCDremained poorly understood. Here we use bioinformatics combined with molecular and biochemical analyses and show that inE. coli, fructoselysine metabolism is tightly controlled at the transcriptional level. The global regulator Crp (CAP), as well as the alternative sigma factor σ32 (RpoH) …
"Table 4" of "Measurement of the g p -> K^0 Sigma^+ reaction with the Crystal Ball/TAPS detectors at the Mainz Microtron"
2014
The recoil polarization of the SIGMA+ for photon energy 1275, 1325, 1375 and 1425 MeV.
"Table 3" of "Measurement of the g p -> K^0 Sigma^+ reaction with the Crystal Ball/TAPS detectors at the Mainz Microtron"
2014
The recoil polarization of the SIGMA+ for photon energy 1125, 1175 and 1225 MeV.
"Table 2" of "Measurement of the g p -> K^0 Sigma^+ reaction with the Crystal Ball/TAPS detectors at the Mainz Microtron"
2014
The differential cross section for photon energies 1275, 1325, 1375 and 1425 MeV.
"Table 1" of "Measurement of the g p -> K^0 Sigma^+ reaction with the Crystal Ball/TAPS detectors at the Mainz Microtron"
2014
The differential cross section for photon energies 1125, 1175 and 1225 MeV.
A non-perturbative study of massive gauge theories
2013
We consider a non-perturbative formulation of an SU(2) massive gauge theory on a space-time lattice, which is also a discretised gauged non-linear chiral model. The lattice model is shown to have an exactly conserved global SU(2) symmetry. If a scaling region for the lattice model exists and the lightest degrees of freedom are spin one vector particles with the same quantum numbers as the conserved current, we argue that the most general effective theory describing their low-energy dynamics must be a massive gauge theory. We present results of a exploratory numerical simulation of the model and find indications for the presence of a scaling region where both a triplet vector and a scalar re…
Finite size spectrum of SU(N) principal chiral field from discrete Hirota dynamics
2016
Using recently proposed method of discrete Hirota dynamics for integrable (1+1)D quantum field theories on a finite space circle of length L, we derive and test numerically a finite system of nonlinear integral equations for the exact spectrum of energies of SU(N)xSU(N) principal chiral field model as functions of m L, where m is the mass scale. We propose a determinant solution of the underlying Y-system, or Hirota equation, in terms of determinants (Wronskians) of NxN matrices parameterized by N-1 functions of the spectral parameter, with the known analytical properties at finite L. Although the method works in principle for any state, the explicit equations are written for states in the …
THE PARISI–SOURLAS MECHANISM IN YANG–MILLS THEORY?
1999
The Parisi-Sourlas mechanism is exhibited in pure Yang-Mills theory. Using the new scalar degrees of freedom derived from the non-linear gauge condition, we show that the non-perturbative sector of Yang-Mills theory is equivalent to a 4D O(1,3) sigma model in a random field. We then show that the leading term of this equivalent theory is invariant under supersymmetry transformations where (x^{2}+\thetabar\theta) is unchanged. This leads to dimensional reduction proving the equivalence of the non-perturbative sector of Yang-Mills theory to a 2D O(1,3) sigma model.
Free field realization of cylindrically symmetric Einstein gravity
1998
Cylindrically reduced Einstein gravity can be regarded as an $SL(2,R)/SO(2)$ sigma model coupled to 2D dilaton gravity. By using the corresponding 2D diffeomorphism algebra of constraints and the asymptotic behaviour of the Ernst equation we show that the theory can be mapped by a canonical transformation into a set of free fields with a Minkowskian target space. We briefly discuss the quantization in terms of these free-field variables, which is considerably simpler than in the other approaches.
Fixed points of nonlinear sigma models in d>2
2009
Using Wilsonian methods, we study the renormalization group flow of the Nonlinear Sigma Model in any dimension $d$, restricting our attention to terms with two derivatives. At one loop we always find a Ricci flow. When symmetries completely fix the internal metric, we compute the beta function of the single remaining coupling, without any further approximation. For $d>2$ and positive curvature, there is a nontrivial fixed point, which could be used to define an ultraviolet limit, in spite of the perturbative nonrenormalizability of the theory. Potential applications are briefly mentioned.