ASCA Observations of Two Ultra-Luminous Compact X-Ray Sources in the Edge-on Spiral Galaxy NGC 4565

The edge-on spiral galaxy NGC 4565 was observed for $\sim$ 35 ks with ASCA in the 0.5-10 keV energy band. The X-ray emission was dominated by two bright sources, which can be identified with two point-like X-ray sources seen in the ROSAT HRI image. The observed 0.5-10 keV fluxes of these sources, $1.7 \times 10^{-12} erg/s cm^{-2}$ and $0.7 \times 10^{-12}erg/s cm^{-2}$, %$1.66 \times 10^{-12} erg/s cm^{-2}$ %$0.66 \times 10^{-12} erg/s cm^{-2}$ imply bolometric luminosities of $1.0\times 10^{40} erg/s$ and $4 \times 10^{39} erg/s$, respectively. They exhibit similar spectra, which can be explained by emission from optically thick accretion disks with the inner disk temperature of 1.4-1.6 keV. One of them, coincident in position with the nucleus, shows too low absorption to be the active nucleus seen through the galaxy disk. Their spectra and high luminosities suggest that they are both mass accreting black hole binaries. However the black-hole mass required by the Eddington limit is rather high ($\geq 50 M_{\odot}$), and the observed disk temperature is too high to be compatible with the high black-hole mass. Several attempts are made to solve these problesms.Comment: 20page

Untangling the complexity of market competition in consumer goods -A complex Hilbert PCA analysis

Today's consumer goods markets are rapidly evolving with significant growth in the number of information media as well as the number of competitive products. In this environment, obtaining a quantitative grasp of heterogeneous interactions of firms and customers, which have attracted interest of management scientists and economists, requires the analysis of extremely high-dimensional data. Existing approaches in quantitative research could not handle such data without any reliable prior knowledge nor strong assumptions. Alternatively, we propose a novel method called complex Hilbert principal component analysis (CHPCA) and construct a synchronization network using Hodge decomposition. CHPCA enables us to extract significant comovements with a time lead/delay in the data, and Hodge decomposition is useful for identifying the time-structure of correlations. We apply this method to the Japanese beer market data and reveal comovement of variables related to the consumer choice process across multiple products. Furthermore, we find remarkable customer heterogeneity by calculating the coordinates of each customer in the space derived from the results of CHPCA. Lastly, we discuss the policy and managerial implications, limitations, and further development of the proposed method.Comment: 27 pages with 9 Figures and 7 Tables, including a 2-page Appendi

An integrated stratigraphy around the Plio-Pleistocene boundary in the Chikura Group, the Boso Peninsula, central Japan, based on data from paleomagnetic, oxygen isotopic and widespread tephra correlation

As widespread tephra is considered to have been deposited widely in an extremely short time after volcanic eruption, it has an important role as a useful geological time index. To improve the accuracy of tephrochronology, we propose a widespread tephra correlation based on various characteristics of the tephra layers for the middle section of the Chikura Group from the southernmost part of the Boso Peninsula, Japan, with a refined chronorostratigraphy based on magnetostratigraphy and oxygen isotopic stratigraphic analysis of benthic foraminifers. Around the Plio-Pleistocene boundary, we were able to compare seven tephra layers with the other tephra layers in Plio-Pleistocene strata in central Japan, and were able to obtain a detailed tephrochronology. The improved accuracy of the integrated tephrochronology is expected to contribute to the understanding of environmental changes over time

Phenotypic Characterization of Transgenic Mice Overexpressing Neuregulin-1

BACKGROUND: Neuregulin-1 (NRG1) is one of the susceptibility genes for schizophrenia and implicated in the neurotrophic regulation of GABAergic and dopaminergic neurons, myelination, and NMDA receptor function. Postmortem studies often indicate a pathologic association of increased NRG1 expression or signaling with this illness. However, the psychobehavioral implication of NRG1 signaling has mainly been investigated using hypomorphic mutant mice for individual NRG1 splice variants. METHODOLOGY/PRINCIPAL FINDINGS: To assess the behavioral impact of hyper NRG1 signaling, we generated and analyzed two independent mouse transgenic (Tg) lines carrying the transgene of green fluorescent protein (GFP)-tagged type-1 NRG1 cDNA. The promoter of elongation-factor 1α gene drove ubiquitous expression of GFP-tagged NRG1 in the whole brain. As compared to control littermates, both heterozygous NRG1-Tg lines showed increased locomotor activity, a nonsignificant trend toward decreasing prepulse inhibition, and decreased context-dependent fear learning but exhibited normal levels of tone-dependent learning. In addition, social interaction scores in both Tg lines were reduced in an isolation-induced resident-intruder test. There were also phenotypic increases in a GABAergic marker (parvalbumin) as well as in myelination markers (myelin basic protein and 2',3'-cyclic nucleotide 3'-phosphodiesterase) in their frontal cortex, indicating the authenticity of NRG1 hyper-signaling, although there were marked decreases in tyrosine hydroxylase levels and dopamine content in the hippocampus. CONCLUSIONS: These findings suggest that aberrant hyper-signals of NRG1 also disrupt various cognitive and behavioral processes. Thus, neuropathological implication of hyper NRG1 signaling in psychiatric diseases should be evaluated with further experimentation

Nonlinear Optical Response in two-dimensional Mott Insulators

We study the third-order nonlinear optical susceptibility $\chi^{(3)}$ and photoexcited states of two-dimensional (2D) Mott insulators by using an effective model in the strong-coupling limit of a half-filled Hubbard model. In the numerically exact diagonalization calculations on finite-size clusters, we find that the coupling of charge and spin degrees of freedom plays a crucial role in the distribution of the dipole-allowed states with odd parity and the dipole-forbidden states with even parity in the photoexcited states. This is in contrast with the photoexcited states in one dimension, where the charge and spin degrees of freedom are decoupled. In the third-harmonic generation (THG) spectrum, main contribution is found to come from the process of three-photon resonance associated with the odd-parity states. As a result, the two-photon resonance process is less pronounced in the THG spectrum. The calculated THG spectrum is compared with recent experimental data. We also find that $\chi^{(3)}$ with cross-polarized configuration of pump and probe photons shows spectral distributions similar to $\chi^{(3)}$ with co-polarized configuration, although the weight is small. These findings will help the analyses of the experimental data of $\chi^{(3)}$ in the 2D Mott insulators.Comment: 9 pages,5 figures,RevTeX