394 research outputs found
Shareholding Networks in Japan
The Japanese shareholding network existing at the end of March 2002 is
studied empirically. The network is constructed from 2,303 listed companies and
53 non-listed financial institutions. We consider this network as a directed
graph by drawing edges from shareholders to stock corporations. The lengths of
the shareholder lists vary with the companies, and the most comprehensive lists
contain the top 30 shareholders. Consequently, the distribution of incoming
edges has an upper bound, while that of outgoing edges has no bound. The
distribution of outgoing degrees is well explained by the power law function
with an exponential tail. The exponent in the power law range is gamma=1.7. To
understand these features from the viewpoint of a company's growth, we consider
the correlations between the outgoing degree and the company's age, profit, and
total assets.Comment: 10 pages, 4 figures, International Conference Science of Complex
Networks: from Biology to the Internet and WWW (CNET2004
Crosstalk Between Intestinal Microbiota Derived Metabolites and Tissues in Allogeneic Hematopoietic Cell Transplantation
Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is an evidence based- cellular immunotherapy for hematological malignancies. Immune reactions not only promote graft-versus-tumor effects that kill hematological malignant cells but also graft-versus-host disease (GVHD) that is the primary complication characterized by systemic organ damages consisting of T-cells and antigen presenting cells (APCs) activation. GVHD has long been recognized as an immunological reaction that requires an immunosuppressive treatment targeting immune cells. However immune suppression cannot always prevent GVHD or effectively treat it once it has developed. Recent studies using high-throughput sequencing technology investigated the impact of microbial flora on GVHD and provided profound insights of the mechanism of GVHD other than immune cells. Allo-HSCT affects the intestinal microbiota and microbiome-metabolome axis that can alter intestinal homeostasis and the severity of experimental GVHD. This axis can potentially be manipulated via dietary intervention or metabolites produced by intestinal bacteria affected post-allo-HSCT. In this review, we discuss the mechanism of experimental GVHD regulation by the complex microbial community-metabolites-host tissue axis. Furthermore, we summarize the major findings of microbiome-based immunotherapeutic approaches that protect tissues from experimental GVHD. Understanding the complex relationships between gut microbiota-metabolites-host tissues axis provides crucial insight into the pathogenesis of GVHD and advances the development of new therapeutic approaches
Seasonal variation of radial brightness contrast of Saturn's rings viewed in mid-infrared by Subaru/COMICS
Aims. To investigate the mid-infrared (MIR) characteristics of Saturn's
rings. Methods. We collected and analyzed MIR high spatial resolution images of
Saturn's rings obtained in January 2008 and April 2005 with COMICS mounted on
Subaru Telescope, and investigated the spatial variation in the surface
brightness of the rings in multiple bands in the MIR. We also composed the
spectral energy distributions (SEDs) of the C, B, and A rings and the Cassini
Division, and estimated the temperatures of the rings from the SEDs assuming
the optical depths. Results. We find that the C ring and the Cassini Division
were warmer than the B and A rings in 2008, which could be accounted for by
their lower albedos, lower optical depths, and smaller self-shadowing effect.
We also find that the C ring and the Cassini Division were considerably
brighter than the B and A rings in the MIR in 2008 and the radial contrast of
the ring brightness is the inverse of that in 2005, which is interpreted as a
result of a seasonal effect with changing elevations of the sun and observer
above the ring plane.Comment: 8 pages, 6 figures, accepted for publication in Astronomy &
Astrophysic
Labour Productivity Superstatistics
We discuss superstatistics theory of labour productivity. Productivity
distribution across workers, firms and industrial sectors are studied
empirically and found to obey power-distributions, in sharp contrast to the
equilibrium theories of mainstream economics. The Pareto index is found to
decrease with the level of aggregation, {\it i.e.}, from workers to firms and
to industrial sectors. In order to explain these phenomenological laws, we
propose a superstatistics framework, where the role of the fluctuating
temperature is played by the fluctuating demand.Comment: 13 pages including figure
Structure and temporal change of the credit network between banks and large firms in Japan
We present a new approach to understanding credit relationships between
commercial banks and quoted firms, and with this approach, examine the temporal
change in the structure of the Japanese credit network from 1980 to 2005. At
each year, the credit network is regarded as a weighted bipartite graph where
edges correspond to the relationships and weights refer to the amounts of
loans. Reduction in the supply of credit affects firms as debtor, and failure
of a firm influences banks as creditor. To quantify the dependency and
influence between banks and firms, we propose a set of scores of banks and
firms, which can be calculated by solving an eigenvalue problem determined by
the weight of the credit network. We found that a few largest eigenvalues and
corresponding eigenvectors are significant by using a null hypothesis of random
bipartite graphs, and that the scores can quantitatively describe the stability
or fragility of the credit network during the 25 years
- …