29,127 research outputs found
Supersymmetric methods in the traveling variable: inside neurons and at the brain scale
We apply the mathematical technique of factorization of differential
operators to two different problems. First we review our results related to the
supersymmetry of the Montroll kinks moving onto the microtubule walls as well
as mentioning the sine-Gordon model for the microtubule nonlinear excitations.
Second, we find analytic expressions for a class of one-parameter solutions of
a sort of diffusion equation of Bessel type that is obtained by supersymmetry
from the homogeneous form of a simple damped wave equations derived in the
works of P.A. Robinson and collaborators for the corticothalamic system. We
also present a possible interpretation of the diffusion equation in the brain
contextComment: 14 pages, 1 figur
Clumpy Disc and Bulge Formation
We present a set of hydrodynamical/Nbody controlled simulations of isolated
gas rich galaxies that self-consistently include SN feedback and a detailed
chemical evolution model, both tested in cosmological simulations. The initial
conditions are motivated by the observed star forming galaxies at z ~ 2-3. We
find that the presence of a multiphase interstellar media in our models
promotes the growth of disc instability favouring the formation of clumps which
in general, are not easily disrupted on timescales compared to the migration
time. We show that stellar clumps migrate towards the central region and
contribute to form a classical-like bulge with a Sersic index, n > 2. Our
physically-motivated Supernova feedback has a mild influence on clump survival
and evolution, partially limiting the mass growth of clumps as the energy
released per Supernova event is increased, with the consequent flattening of
the bulge profile. This regulation does not prevent the building of a
classical-like bulge even for the most energetic feedback tested. Our Supernova
feedback model is able to establish a self-regulated star formation, producing
mass-loaded outflows and stellar age spreads comparable to observations. We
find that the bulge formation by clumps may coexit with other channels of bulge
assembly such as bar and mergers. Our results suggest that galactic bulges
could be interpreted as composite systems with structural components and
stellar populations storing archaeological information of the dynamical history
of their galaxy.Comment: Accepted for publication in MNRAS - Aug. 20, 201
ROCOV scheme for Fault Detection and Location in HVDC sytems
A reliable DC fault protection system is essential
for the development of HVDC grids. Therefore, this paper deals
with the voltage derivative ROCOV scheme to locate and detect
DC faults. The algorithm is able to differentiate internal and
external faults considerably fast. The proposed algorithm is
analyzed in a HVDC grid with different fault case scenarios.
Finally, the ROCOV protection thresholds are discussed.The authors thank the support from the Spanish Ministry of
Economy, Industry and Competitiveness (project
ENE2016-79145-R AEI/FEDER, UE) and GISEL research
group IT1083-16), as well as from the University of the
Basque Country UPV/EHU (research group funding
PPG17/23)
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