3,117 research outputs found
Effects of degree distribution in mutual synchronization of neural networks
We study the effects of the degree distribution in mutual synchronization of
two-layer neural networks. We carry out three coupling strategies: large-large
coupling, random coupling, and small-small coupling. By computer simulations
and analytical methods, we find that couplings between nodes with large degree
play an important role in the synchronization. For large-large coupling, less
couplings are needed for inducing synchronization for both random and
scale-free networks. For random coupling, cutting couplings between nodes with
large degree is very efficient for preventing neural systems from
synchronization, especially when subnetworks are scale-free.Comment: 5 pages, 4 figure
Walks on weighted networks
We investigate the dynamics of random walks on weighted networks. Assuming
that the edge's weight and the node's strength are used as local information by
a random walker, we study two kinds of walks, weight-dependent walk and
strength-dependent walk. Exact expressions for stationary distribution and
average return time are derived and confirmed by computer simulations. We
calculate the distribution of average return time and the mean-square
displacement for two walks on the BBV networks, and find that a
weight-dependent walker can arrive at a new territory more easily than a
strength-dependent one.Comment: 4 pages, 5 figures. minor modifications. Comments and suggestions are
favored by the author
TPH-2 polymorphisms interact with early life stress to influence response to treatment with antidepressant drugs
Background: Variation in genes implicated in monoamine neurotransmission may interact with environmental factors to influence antidepressant response. We aimed to determine how a range of single nucleotide polymorphisms in monoaminergic genes influence this response to treatment and how they interact with childhood trauma and recent life stress in a Chinese sample. An initial study of monoaminergic coding region single nucleotide polymorphisms identified significant associations of TPH2 and HTR1B single nucleotide polymorphisms with treatment response that showed interactions with childhood and recent life stress, respectively (Xu et al., 2012).
Methods: A total of 47 further single nucleotide polymorphisms in 17 candidate monoaminergic genes were genotyped in 281 Chinese Han patients with major depressive disorder. Response to 6 weeksâ antidepressant treatment was determined by change in the 17-item Hamilton Depression Rating Scale score, and previous stressful events were evaluated by the Life Events Scale and Childhood Trauma Questionnaire-Short Form.
Results: Three TPH2 single nucleotide polymorphisms (rs11178998, rs7963717, and rs2171363) were significantly associated with antidepressant response in this Chinese sample, as was a haplotype in TPH2 (rs2171363 and rs1487278). One of these, rs2171363, showed a significant interaction with childhood adversity in its association with antidepressant response.
Conclusions: These findings provide further evidence that variation in TPH2 is associated with antidepressant response and may also interact with childhood trauma to influence outcome of antidepressant treatment
Virialization of Galaxy Clusters and Beyond
Using samples of structures identified by a multi-scale decomposition from
numerical simulation, we analyze the scale-dependence of the virialization of
clusters. We find that beyond the scale of full virialization there exists a
radius range over which clusters are quasi-virialized, i.e. while the internal
structure of an {\it individual} cluster is at substantial departure from
dynamical relaxation, some {\it statistical} properties of the multi-scale
identified clusters are approximately the same as those for the virialized
systems. The dynamical reason of the existence of quasi-virialization is that
some of the scaling properties of dynamically relaxed systems of cosmic
gravitational clustering approximately hold beyond the full virialization
regime. The "individual-statistical" duality of the quasi-virialization
provides an explanation of the observed puzzle that the total masses of
clusters derived from virial theorem are statistically the same as the
gravitational lensing determined masses, in spite of the presence of irregular
configuration and substructures in individual clusters. It also explains the
tight correlation between the velocity dispersion of optical galaxies and the
temperature of X-ray emitting gas. Consequently, the virial mass estimators
based on the assumptions of isothermal and hydrostatic model are statistically
applicable to scales on which the clusters are quasi-virialized. In the
quasi-virialization regime, the temperature functions of clusters also show
scaling. This feature is a useful discriminator among cosmological models.Comment: AAS Latex file, 22 pages+ 14 figures, accepted for publication in Ap
Generalized parton distributions of gluon in proton: a light-front quantization approach
We solve for the gluon generalized parton distributions (GPDs) inside the
proton, focusing specifically on leading twist chiral-even GPDs. We obtain and
employ the light-front wavefunctions (LFWFs) of the proton from a light-front
quantized Hamiltonian with Quantum Chromodynamics input using basis light-front
quantization (BLFQ). Our investigation incorporates the valence Fock sector
with three constituent quarks and an additional Fock sector, encompassing three
quarks and a dynamical gluon. We examine the GPDs within impact parameter space
and evaluate the -dependence of the transverse square radius. We find that
the transverse size of the gluon at lower- is larger than that of the quark,
while it exhibits opposite behavior at large-. Using the proton spin sum
rule, we also determine the relative contributions of quarks and the gluon to
the total angular momentum of the proton.Comment: 10 pages, 4 figure
Metallic surface states in a correlated d-electron topological Kondo insulator candidate FeSb2
The resistance of a conventional insulator diverges as temperature approaches
zero. The peculiar low temperature resistivity saturation in the 4f Kondo
insulator (KI) SmB6 has spurred proposals of a correlation-driven topological
Kondo insulator (TKI) with exotic ground states. However, the scarcity of model
TKI material families leaves difficulties in disentangling key ingredients from
irrelevant details. Here we use angle-resolved photoemission spectroscopy
(ARPES) to study FeSb2, a correlated d-electron KI candidate that also exhibits
a low temperature resistivity saturation. On the (010) surface, we find a rich
assemblage of metallic states with two-dimensional dispersion. Measurements of
the bulk band structure reveal band renormalization, a large
temperature-dependent band shift, and flat spectral features along certain high
symmetry directions, providing spectroscopic evidence for strong correlations.
Our observations suggest that exotic insulating states resembling those in SmB6
and YbB12 may also exist in systems with d instead of f electrons
Transverse momentum structure of strange and charmed baryons: a light-front Hamiltonian approach
Under the basis light-front quantization framework, we investigate the
leading-twist transverse-momentum-dependent parton distribution functions
(TMDs) for and baryons, the spin-1/2 composite systems
consisting of two light quarks ( and ) and a quark. We evaluate the
TMDs using the overlaps of the light-front wave functions in the leading Fock
sector, which are obtained by solving the light-front eigenvalue equation. We
also study the spin densities of quarks in momentum space for various
polarizations. In the same model, we compare the TMDs of the strange and
charmed baryons and the proton by reviewing their spin structures in the quark
model and the probabilistic interpretations of their TMDs.Comment: 18 pages, 6 figure
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