840 research outputs found
Emergence of (bi)multi-partiteness in networks having inhibitory and excitatory couplings
(Bi)multi-partite interaction patterns are commonly observed in real world
systems which have inhibitory and excitatory couplings. We hypothesize these
structural interaction pattern to be stable and naturally arising in the course
of evolution. We demonstrate that a random structure evolves to the
(bi)multi-partite structure by imposing stability criterion through
minimization of the largest eigenvalue in the genetic algorithm devised on the
interacting units having inhibitory and excitatory couplings. The evolved
interaction patterns are robust against changes in the initial network
architecture as well as fluctuations in the interaction weights.Comment: 6 pages, 7 figure
Overview: institutions and policies for water resources management
Water PolicyParticipatory managementIrrigation waterEconomic valueWater supply
Optimization of synchronizability in multiplex networks
We investigate the optimization of synchronizability in multiplex networks
and demonstrate that the interlayer coupling strength is the deciding factor
for the efficiency of optimization. The optimized networks have homogeneity in
the degree as well as in the betweenness centrality. Additionally, the
interlayer coupling strength crucially affects various properties of individual
layers in the optimized multiplex networks. We provide an understanding to how
the emerged network properties are shaped or affected when the evolution
renders them better synchronizable.Comment: 6 pages and 6 figure
Optimization of synchronizability in multiplex networks by rewiring one layer
Peer reviewedPublisher PD
Vertical magnetic field gradient in the photospheric layers of sunspots
We investigate the vertical gradient of the magnetic field of sunspots in the
photospheric layer. Independent observations were obtained with the SOT/SP
onboard the Hinode spacecraft and with the TIP-2 mounted at the VTT. We apply
state-of-the-art inversion techniques to both data sets to retrieve the
magnetic field and the corresponding vertical gradient. In the sunspot
penumbrae we detected patches of negative vertical gradients of the magnetic
field strength, i.e.,the magnetic field strength decreases with optical depth
in the photosphere. The negative gradient patches are located in the inner and
partly in the middle penumbrae in both data sets. From the SOT/SP observations,
we found that the negative gradient patches are restricted mainly to the deep
photospheric layers and are concentrated near the edges of the penumbral
filaments. MHD simulations also show negative gradients in the inner penumbrae,
also at the locations of filaments. Both in the observations and simulation
negative gradients of the magnetic field vs. optical depth dominate at some
radial distances in the penumbra. The negative gradient with respect to optical
depth in the inner penumbrae persists even after averaging in the azimuthal
direction, both in the observations and, to a lesser extent, also in MHD
simulations. We interpret the observed localized presence of the negative
vertical gradient of the magnetic field strength in the observations as a
consequence of stronger field from spines expanding with height and closing
above the weaker field inter-spines. The presence of the negative gradients
with respect to optical depth after azimuthal averaging can be explained by two
different mechanisms: the high corrugation of equal optical depth surfaces and
the cancellation of polarized signal due to the presence of unresolved opposite
polarity patches in the deeper layers of the penumbra.Comment: 17 pages, 25 figures, accepted for publication in A&
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