2,070 research outputs found
Analytical controllability of deterministic scale-free networks and Cayley trees
According to the exact controllability theory, the controllability is
investigated analytically for two typical types of self-similar bipartite
networks, i.e., the classic deterministic scale-free networks and Cayley trees.
Due to their self-similarity, the analytical results of the exact
controllability are obtained, and the minimum sets of driver nodes (drivers)
are also identified by elementary transformations on adjacency matrices. For
these two types of undirected networks, no matter their links are unweighted or
(nonzero) weighted, the controllability of networks and the configuration of
drivers remain the same, showing a robustness to the link weights. These
results have implications for the control of real networked systems with
self-similarity.Comment: 7 pages, 4 figures, 1 table; revised manuscript; added discussion
about the general case of DSFN; added 3 reference
Causal Relationship among the National Wealth, the Consumption and Shanghai Composite Index
Based on data between the December 1990 to July 2009 of the industrial added value, retail sales and the Shanghai composite index, Cointegration and Granger Causality test have been done and found that: a) An stable cointegration relationship exists among the industrial added value, retail sales and Shanghai composite index, and they are positively correlated. b) The total industrial added value and retail sales Granger cause the Shanghai composite index, but the reverse affect did not observed, which explain China's stock market is not yet a mature market. c) Compared to the total retail sales, the impact of industrial added value on the Shanghai composite index delayed a little longer.Keywords: cointegration test; Granger causality test; industrial added value; total retail sales; the Shanghai Composite Inde
Dimensional crossover of thermal conductance in graphene nanoribbons: A first-principles approach
First-principles density-functional calculations are performed to investigate
the thermal transport properties in graphene nanoribbons (GNRs). The
dimensional crossover of thermal conductance from one to two dimensions (2D) is
clearly demonstrated with increasing ribbon width. The thermal conductance of
GNRs in a few nanometer width already exhibits an approximate low-temperature
dependence of , like that of 2D graphene sheet which is attributed to
the quadratic nature of dispersion relation for the out-of-plane acoustic
phonon modes. Using a zone-folding method, we heuristically derive the
dimensional crossover of thermal conductance with the increase of ribbon width.
Combining our calculations with the experimental phonon mean-free path, some
typical values of thermal conductivity at room temperature are estimated for
GNRs and for 2D graphene sheet, respectively. Our findings clarify the issue of
low-temperature dependence of thermal transport in GNRs and suggest a
calibration range of thermal conductivity for experimental measurements in
graphene-based materials.Comment: 18 pages, 4 figure
Global and partitioned reconstructions of undirected complex networks
It is a significant challenge to predict the network topology from a small
amount of dynamical observations. Different from the usual framework of the
node-based reconstruction, two optimization approaches (i.e., the global and
partitioned reconstructions) are proposed to infer the structure of undirected
networks from dynamics. These approaches are applied to evolutionary games
occurring on both homogeneous and heterogeneous networks via compressed
sensing, which can more efficiently achieve higher reconstruction accuracy with
relatively small amounts of data. Our approaches provide different perspectives
on effectively reconstructing complex networks.Comment: 6 pages, 2 figures, 1 table; revised version; added numerical results
of the PR in Table 1 and expanded Section 4; added 7 reference
Molecular cloning and antibacterial activity of hepcidin from Chinese rare minnow (Gobiocypris rarus)
AbstractBackgroundHepcidins, a kind of cysteine-rich antimicrobial peptides, play important roles in host immunological processes and iron regulation, which have been identified from several fish species. The rare minnow (Gobiocypris rarus), an endemic cyprinid fish in China, has been used extensively as model animal in laboratory. However, little is known about its hepcidin. Here, we report the cloning and characterization of a hepcidin gene from the liver of Chinese rare minnow.ResultsThe full-length cDNA of rare minnow hepcidin is 662bp, which contains an ORF of 273bp encoding a prepropeptide of 90 amino acid residues. The predicted prepropeptide contains three domains: a signal peptide of 24 amino acids, a prodomain of 41 amino acids, and a mature peptide of 25 amino acids. Sequence alignment showed eight conserved cysteine residues in the mature peptide, which formed four disulfide bonds in spatial structure. The deduced structure of mature peptide showed a high degree of homology to the human hepcidin. Phylogenetic analysis showed that it had a close relationship with zebrafish hepcidin, and clustered in a clade with these from Cyprinidae. Synthetic peptide of rare minnow hepcidin could inhibit the growth of Gram positive bacterium Staphylococcus aureus and Gram negative bacteria Escherichia coli and Aeromonas hydrophila.ConclusionThese results suggested that rare minnow hepcidin had typical structure of hepcidins and antibacterial activity. It could participate in innate immune response as an antibacterial agent and be used as antibiotic substance
2,4-Dichloro-7-fluoroquinazoline
The molecule of the title compound, C8H3Cl2FN2, is essentially planar, with a maximum deviation of 0.018 (2) Å. In the crystal, π–π stacking is observed between parallel quinazoline moieties of adjacent molecules, the centroid–centroid distance being 3.8476 (14) Å
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