9,194 research outputs found
An update on transcriptional and post-translational regulation of brain voltage-gated sodium channels
Voltage-gated sodium channels are essential proteins in brain physiology, as they generate the sodium currents that initiate neuronal action potentials. Voltage-gated sodium channels expression, localisation and function are regulated by a range of transcriptional and post-translational mechanisms. Here, we review our understanding of regulation of brain voltage-gated sodium channels, in particular SCN1A (Naᔄ1.1), SCN2A (Naᔄ1.2), SCN3A (Naᔄ1.3) and SCN8A (Naᔄ1.6), by transcription factors, by alternative splicing, and by post-translational modifications. Our focus is strongly centred on recent research lines, and newly generated knowledge
Partition function of the Potts model on self-similar lattices as a dynamical system and multiple transitions
We present an analytic study of the Potts model partition function on two
different types of self-similar lattices of triangular shape with non integer
Hausdorff dimension. Both types of lattices analyzed here are interesting
examples of non-trivial thermodynamics in less than two dimensions. First, the
Sierpinski gasket is considered. It is shown that, by introducing suitable
geometric coefficients, it is possible to reduce the computation of the
partition function to a dynamical system, whose variables are directly
connected to (the arising of) frustration on macroscopic scales, and to
determine the possible phases of the system. The same method is then used to
analyse the Hanoi graph. Again, dynamical system theory provides a very elegant
way to determine the phase diagram of the system. Then, exploiting the analysis
of the basins of attractions of the corresponding dynamical systems, we
construct various examples of self-similar lattices with more than one critical
temperature. These multiple critical temperatures correspond to crossing phases
with different degrees of frustration.Comment: 16 pages, 12 figures, 1 table; title changed, references and
discussion on multiple transitions adde
Local supersymmetry without SUSY partners
A gauge theory for a superalgebra that includes an internal gauge (G) and
local Lorentz algebras, and that could describe the low energy particle
phenomenology is constructed. These two symmetries are connected by fermionic
supercharges. The system includes an internal gauge connection 1-form , a
spin-1/2 Dirac spinor , the Lorentz connection , and the vielbein
. The connection one-form is in the adjoint representation of G, while
is in the fundamental. In contrast to standard supergravity, the metric
is not a fundamental field and is in the center of the superalgebra: it is not
only invariant under the internal gauge group and under Lorentz
transformations, but is also invariant under supersymmetry. The features of
this theory that mark the difference with standard supersymmetry are: A) The
number of fermionic and bosonic states is not necessarily the same; B) There
are no superpartners with equal mass, "bosoninos", sleptons and squarks are
absent; C) Although this supersymmetry originates in a local gauge theory and
gravity is included, there is no gravitino; D) Fermions acquire mass from their
coupling to the background or from self-couplings, while bosons remain
massless. In odd dimensions, the Chern-Simons form provides an action that is
quasi-invariant under the entire superalgebra. In even dimensions, the
Yang-Mills form is the only natural option, and the symmetry breaks
down to [G x SO(1,D-1)]. In 4D, the construction follows the Townsend - Mac
Dowell-Mansouri approach. Due to the absence of osp(4|2)-invariant traces in
four dimensions, the resulting Lagrangian is only invariant under [U(1) x
SO(3,1)], and includes a Nambu--Jona-Lasinio term. In this case, the Lagrangian
depends on a single dimensionful parameter that fixes Newton's constant, the
cosmological constant and the NJL coupling.Comment: 24 pages, no figures. Title changed in journal version to
"Unconventional supersymmetry and its breaking". Few references added and
some paragraphs rewritten from v.1. This version includes two appendices that
are not found in the journal versio
A two particle hidden sector and the oscillations with photons
We present a detailed study of the oscillations and optical properties for
vacuum, in a model for the dark sector that contains axion-like particles and
hidden photons. In this model, both can couple to photons. We provide bounds
for the couplings versus the mass, using current results from ALPS-I and PVLAS.
We also discuss the challenges for the detection of models with more than one
hidden particle in light shining trough wall-like experiments.Comment: 23 pages, 7 figures. Figures are coloure
The Role of Fundamentals in the Price of Housing. Theory and Evidence
Despite the extensive research in the field of housing economics, the role of some âfundamentalâ economic variables, such as income, interest rates or stock of houses per capita, on the real price of housing is still not fully understood. In this paper we develop a dynamic general equilibrium model to micro-fundament the price of housing in a market without renting. In this framework we underline the dual role of housing both as a good that produces valuable services and as an investment asset that can be resold in a future date. To test the theoretical results obtained, we analyze the Spanish housing market from 1995 to 2006 as it seems to satisfy the theoretical assumptions in practice. We examine the extent to which real house prices at the regional level are driven by fundamentals by applying Panel Cointegration methods such as Common Correlated Effects, Dynamic Ordinary Least Squares and Vector Error Correction. Results are fully consistent with the theory and underline the importante of both long-run adjustment and persistence processes to explain the dynamic behaviour of prices.Panel Cointegration, housing prices, adjustment dynamics, macroeconomic model
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