2,385 research outputs found
Temporal similarity metrics for latent network reconstruction: The role of time-lag decay
When investigating the spreading of a piece of information or the diffusion
of an innovation, we often lack information on the underlying propagation
network. Reconstructing the hidden propagation paths based on the observed
diffusion process is a challenging problem which has recently attracted
attention from diverse research fields. To address this reconstruction problem,
based on static similarity metrics commonly used in the link prediction
literature, we introduce new node-node temporal similarity metrics. The new
metrics take as input the time-series of multiple independent spreading
processes, based on the hypothesis that two nodes are more likely to be
connected if they were often infected at similar points in time. This
hypothesis is implemented by introducing a time-lag function which penalizes
distant infection times. We find that the choice of this time-lag strongly
affects the metrics' reconstruction accuracy, depending on the network's
clustering coefficient and we provide an extensive comparative analysis of
static and temporal similarity metrics for network reconstruction. Our findings
shed new light on the notion of similarity between pairs of nodes in complex
networks
A differential game model research on dynamic pricing and coordination of fresh agricultural products supply chain based on freshness
For the problem of optimal dynamic pricing and coordination of
fresh agricultural products supply chain, the differential equations
related to freshness and market needs are constructed, and the
optimal control theory is used to solve the optimal strategy under
centralized and decentralized decision-making, i.e., optimal selling
price and optimal preservation input. The equilibrium results
under the two scenarios are also compared. The comparison finds
that the decentralized scenario leads to low overall supply chain
profits, based on which a two-part pricing contract is proposed to
coordinate the supply chain operating companies. The results
show that freshness effectiveness directly impacts pricing, and the
centralized scenario does not necessarily lead to high prices for
fresh produce due to the ‘double marginal effect’. the two pricing
contracts can successfully coordinate the supply chain. The freshness
effectiveness increases the supply chain coordination ability
of fresh produce suppliers, while operational inefficiencies, on the
contrary, decrease the coordination abilit
Cleavage of lamin-like proteins in in vivo and in vitro apoptosis of tobacco protoplasts induced by heat shock
AbstractApoptosis in heat shock-treated tobacco protoplasts was evidenced by DNA fragmentation, flow cytometric analysis and activation of caspase 3-like protease. Furthermore, an in vitro apoptosis system was established which reproduced the apoptotic events. Western blotting analysis using an antibody against lamin A and C showed that in both in vivo and in vitro systems lamin-like proteins were cleaved into a 35-kDa fragment, and that lamin-like protein degradation precedes DNA fragmentation. Moreover, we found a 22.8-fold increase in caspase 6-like activity in cytosol of heat-treated protoplasts as compared with the control
Seismic visibility of eclogite in the Earth’s upper mantle – implications from high pressure-temperature single-crystal elastic properties of omphacite
Eclogite, constituting the subducted crust, is one of the most important geochemical and geophysical heterogeneities in the Earth’s mantle. As the dominant anisotropic phase in eclogite, precise high pressure-temperature single-crystal elastic properties of omphacite provides the basis for detecting eclogite in the Earth’s upper mantle. In this study, we measured the single-crystal elastic moduli of omphacite up to 18 GPa and 700 K using Brillouin spectroscopy. A least-squares fit to a third-order finite strain equation of state yields KS0’=4.5(1), G0’=1.53(5), ∂KS0/∂T=-0.029(5) GPa/K, ∂G0/∂T=-0.013(5) GPa/K, with ρ0=3.34(1) g/cm3, KS0=123(3) GPa, and G0=74(2) GPa. We found that the seismic velocities of eclogite are similar to pyrolite at the depths of 200-300 and 410-500 km, thus eclogite is seismically invisible at these depths. Combined with the lattice-preferred orientations of the omphacite in naturally deformed eclogites, we also modeled seismic anisotropy of eclogite at various pressure-temperature conditions
Tests of relative vertical offsets for several types of GPS receiver antenna phase centers
AbstractThe correction for antenna phase center is considered in processing Global Positioning System (GPS) data collected from a network of GPS ultra-short baselines. Compared with the leveling measurements, the GPS results show that the relative vertical offsets for the pairs of GPS receiver antenna phase centers still exist, although absolute calibration of the antenna phase center variations (PCVs) has been considered. With respect to the TPS CR.G3 antenna, the relative vertical offset for the LEI AT504 antenna is −8.4 mm, the offset for the ASH701945C_M antenna is 5.5 mm, and those for the ASH700936E_C and ASH701945B_M antennas are approximately between −2 mm and −3 mm. The relative offsets for the same type of antennas are approximately 1 mm. By correcting the absolute PCVs, the existing relative offset becomes negligible for horizontal positioning
Efficient multipartite entanglement purification with non-identical states
We present an efficient and general multipartite entanglement purification
protocol (MEPP) for N-photon systems in Greenberger-Horne-Zeilinger (GHZ)
states with non-identical input states. As a branch of entanglement
purification, besides the cases of successful purification, the recurrence MEPP
actually has the reusable discarded items which are usually regarded as a
failure. Our protocol contains two parts for bit-flip error correction. The
first one is the conventional MEPP, corresponding successful cases. The second
one includes two efficient approaches, recycling purification with entanglement
link and direct residual entanglement purification, that can utilize discarded
items. We also make a comparison between two approaches. Which method to use
depends on initial input states, and in most cases the approach of direct
residual purification is optimal for it not only may obtain a higher fidelity
entangled state but also it does not require additional sophisticated links. In
addition, for phase-flip errors, the discarded items still have available
residual entanglement in the case of different input states. With these
approaches, this MEPP has a higher efficiency than all previous MEPPs and it
may have potential applications in the future long-distance quantum
communications and networks.Comment: 20 pages,12 figure
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