318 research outputs found
Generating functional analysis of complex formation and dissociation in large protein interaction networks
We analyze large systems of interacting proteins, using techniques from the
non-equilibrium statistical mechanics of disordered many-particle systems.
Apart from protein production and removal, the most relevant microscopic
processes in the proteome are complex formation and dissociation, and the
microscopic degrees of freedom are the evolving concentrations of unbound
proteins (in multiple post-translational states) and of protein complexes. Here
we only include dimer-complexes, for mathematical simplicity, and we draw the
network that describes which proteins are reaction partners from an ensemble of
random graphs with an arbitrary degree distribution. We show how generating
functional analysis methods can be used successfully to derive closed equations
for dynamical order parameters, representing an exact macroscopic description
of the complex formation and dissociation dynamics in the infinite system
limit. We end this paper with a discussion of the possible routes towards
solving the nontrivial order parameter equations, either exactly (in specific
limits) or approximately.Comment: 14 pages, to be published in Proc of IW-SMI-2009 in Kyoto (Journal of
Phys Conference Series
1D generalized statistics gas: A gauge theory approach
A field theory with generalized statistics in one space dimension is
introduced. The statistics enters the scene through the coupling of the matter
fields to a statistical gauge field, as it happens in the Chern-Simons theory
in two dimensions. We study the particle-hole excitations and show that the
long wave length physics of this model describes a gas obeying the Haldane
generalized exclusion statistics. The statistical interaction is found to
provide a way to describe the low-T critical properties of one-dimensional
non-Fermi liquids.Comment: 8 pages, revte
Caracterização de folhas de citros utilizando imagens de fluorescência visando o diagnóstico de HLB (Greening).
On the physical interpretation of effective actions using Schwinger's formula
We show explicitly that Schwinger's formula for one-loop effective actions
corresponds to the summation of energies associated with the zero-point
oscillations of the fields. We begin with a formal proof, and after that we
confirm it using a regularization prescription.Comment: 5 p., REVTEX, IF-UFRJ-9
Avaliação da utilização da técnica de espectroscopia de fluorescência induzida por laser na detecção de doenças em citros.
Combinação de cultivo do Coffea arabica, com cedro australiano Toona ciliata var.australis na Região Sul de Minas.
Prediction of metabolizable energy values in poultry offal meal for broiler chickens.
Projeto/Plano de Ação: 16.00.300.04-00
Electromagnetic Response and Approximate SO(5) Symmetry in High-Tc Superconductors
It has been proposed that the effective Hamiltonian describing high T_c
superconductivity in cuprate materials has an approximate SO(5) symmetry
relating the superconducting (SC) and antiferromagnetic (AF) phases of these
systems. We show that robust consequences of this proposal are potentially
large optical conductivities and Raman scattering rates in the AF phase, due to
the electromagnetic response of the doubly-charged pseudo Goldstone bosons
which must exist there. This provides strong constraints on the properties of
the bosons, such as their mass gap and velocity.Comment: 4 pages, 3 figure
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