1,792 research outputs found
Opinion dynamics on directed small-world networks
In this paper, we investigate the self-affirmation effect on formation of
public opinion in a directed small-world social network. The system presents a
non-equilibrium phase transition from a consensus state to a disordered state
with coexistence of opinions. The dynamical behaviors are very sensitive to the
density of long-range interactions and the strength of self-affirmation. When
the long-range interactions are sparse and individual generally does not insist
on his/her opinion, the system will display a continuous phase transition, in
the opposite case with high self-affirmation strength and dense long-range
interactions, the system does not display a phase transition. Between those two
extreme cases, the system undergoes a discontinuous phase transition.Comment: 6 pages, 5 figure
Integrating static and dynamic information for routing traffic
The efficiency of traffic routing on complex networks can be reflected by two
key measurements i.e. the system capacity and the average data packets travel
time. In this paper, we propose a mixing routing strategy by integrating local
static and dynamic information for enhancing the efficiency of traffic on
scale-free networks. The strategy is governed by a single parameter. Simulation
results show that there exists a optimal parameter value by considering both
maximizing the network capacity and reducing the packet travel time. Comparing
with the strategy by adopting exclusive local static information, the new
strategy shows its advantages in improving the efficiency of the system. The
detailed analysis of the mixing strategy is provided. This work suggests that
how to effectively utilize the larger degree nodes plays the key role in the
scale-free traffic systems.Comment: 5 pages, 5 figure
Static and Dynamic Response Analysis of a High Rock-Fill Dam with a Clay Core
Stress strain analysis based on Biot’s consolidation theory is performed for Nuozhadu dam, which is a high rock-fill clay-core dam located in the Langcangjiang River in Yunnan province, China. Attention is mainly focused on arching effect and possibility of hydraulic fracturing of the core. Equivalent linear approach is employed to evaluate the seismic response of the dam under design earthquakes, and two empirical formulas relating residual shear and volumetric strain to cyclic stress and strain history are proposed to evaluate the permanent deformation. It is found that: 1) the modulus ratio of the clay in the core to rockfills around is the main factor controlling the severity of arching effect, 2) hydraulic fracture would not occur according to the criterion of effective stress, and 3) the permanent deformation that is likely to occur is acceptable under the condition of design earthquakes
Quasi-Periodic Variations in X-ray Emission and Long-Term Radio Observations: Evidence for a Two-Component Jet in Sw J1644+57
The continued observations of Sw J1644+57 in X-ray and radio bands
accumulated a rich data set to study the relativistic jet launched in this
tidal disruption event. The X-ray light curve of Sw J1644+57 from 5-30 days
presents two kinds of quasi-periodic variations: a 200 second quasi-periodic
oscillation (QPO) and a 2.7-day quasi-periodic variation. The latter has been
interpreted by a precessing jet launched near the Bardeen-Petterson radius of a
warped disk. Here we suggest that the 200s QPO could be associated with
a second, narrower jet sweeping the observer line-of-sight periodically, which
is launched from a spinning black hole in the misaligned direction with respect
to the black hole's angular momentum. In addition, we show that this
two-component jet model can interpret the radio light curve of the event,
especially the re-brightening feature starting days after the
trigger. From the data we infer that inner jet may have a Lorentz factor of
and a kinetic energy of , while the outer jet may have a Lorentz factor of
and a kinetic energy of .Comment: 11 pages, 7 figures, accepted for publication in Ap
Effects of transplanted GDNF gene modified marrow stromal cells on focal cerebral ischemia in rats
Objective: To evaluate the therapeutic effect of transplanted glial cell derived neurotrophic factor (GDNF) modified marrow stromal cells (MSCs) on an experimental ischemic brain injury based on the behavioral, morphological, and immunohistochemical observations. Methods: The MSCs from four-week newborn rats were cultured in vitro. The cerebral ischemia and reperfusion model was established in adult Sprague–Dawley (SD) rats by using the suture method. Three days after model establishment, the animals were injected with prepared MSCs via their caudal veins. The animals were then divided into a sham-operation group, ischemia group, MSCs transplantation group, or GDNF+ MSCs transplantation group and were scored for their neurobehavioral manifestations at 3, 14, and 28 days after the transplantation was performed. At this time, the survival condition of intracerebral transplanted cells was measured by laser confocal microscopy while the effect of transplantation on the Generic Digital Beam Former (GDNF) expression in the ischemic brain tissue was evaluated. Results: The MSCs cells transfected with GDNF gene were characterized by green fluorescence. Three days after the transplantation, the animals that underwent the cell transplantation showed significantly better behavioral data than the controls. Fourteen days after transplantation, the animals transplanted with GDNF gene modified MSCs were better than those transplanted with common MSCs. As compared with common MSCs transplantation, GDNF+MSCs transplantation was significantly more effective in reducing apoptotic cell volume and enhancing Bcl-2 expression, which was favorable for the ischemic brain injury. Conclusions: Transplanted GDNF modified MSCs can improve the nervous function and have a protective effect on the ischemic brain injury through reducing apoptotic cell volume and enhancing the expression of anti-apoptotic gene Bcl-2
Power-law Strength-Degree Correlation From a Resource-Allocation Dynamics on Weighted Networks
Many weighted scale-free networks are known to have a power-law correlation
between strength and degree of nodes, which, however, has not been well
explicated. We investigate the dynamic behaviors of resource/traffic flow on
scale-free networks. The dynamical system will evolve to a kinetic equilibrium
state, where the strength, defined by the amount of resource or traffic load,
is correlated with the degree in a power-law form with tunable exponent. The
analytical results agree with simulations well.Comment: 6 pages, and 8 figure
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