507 research outputs found
Population changes in residential clusters in Japan
Population dynamics in urban and rural areas are different. Understanding
factors that contribute to local population changes has various socioeconomic
and political implications. In the present study, we use population census data
in Japan to examine contributors to the population growth of residential
clusters between years 2005 and 2010. The data set covers the entirety of Japan
and has a high spatial resolution of 500500, enabling us
to examine population dynamics in various parts of the country (urban and
rural) using statistical analysis. We found that, in addition to the area,
population density, and age, the shape of the cluster and the spatial
distribution of inhabitants within the cluster are significantly related to the
population growth rate of a residential cluster. Specifically, the population
tends to grow if the cluster is "round" shaped (given the area) and the
population is concentrate near the center rather than periphery of the cluster.Comment: 3 figures, 4 table
Multi-object and long-slit spectroscopy of very low mass brown dwarfs in the Orion Nebular Cluster
We present the results of an H-and K-band multi-object and long-slit spectroscopic survey of substellar mass candidates in the outer regions of the Orion Nebula Cluster. The spectra were obtained using MOIRCS on the 8.2m Subaru telescope and ISLE on the 1.88m telescope of Okayama Astrophysical Observatory. Eight out of twelve spectra show strong water absorption and we confirm that their effective temperatures are ≤3000K (spectral type ≥M6) from a chi-square fit to synthetic spectra. We plot our sources on an HR diagram overlaid with theoretical isochrones of low-mass objects and identify three new young brown dwarf candidates. One of the three new candidates is a cool object near the brown dwarf and planetary mass boundary. Based on our observations and those of previous studies, we determine the stellar (0.08Peer reviewe
Development of a Typing Skill Learning Environment with Diagnosis and Advice on Fingering Errors
AbstractExisting application software for touch typing training cannot diagnose fingering errors. Given this fact, we developed a skill learning environment for touch typing training that can diagnose fingering errors by recognizing fingers with color markers using image recognition technique. This study developed two systems: a learning support environment for an experimental group and a learning environment for a control group. We evaluated the effect of the learning environment that can diagnose fingering errors for the experimental group, by comparison with the other learning environment for the control group
Near-Infrared Spectroscopy of the Cool Brown Dwarf, SDSS 1624+00
Using the Subaru Telescope, we have obtained multiple near-infrared spectra
of the cool brown dwarf, SDSS 1624+00, in search of spectral variability in an
80 minute time span. We have found the suspected variability of water vapor
absorption throughout the observations, which requires confirmation by a longer
time baseline. After coadding the spectra, we have obtained a high-quality
spectrum covering 1.05 to 1.8 um. Three kinds of spectral indicators, the water
vapor bands, methane band, and KI lines in J band, suggest that SDSS 1624+00 is
warmer and dustier than Gl 229B.Comment: 6 figures, to appear in PAS
Flared Disks and Silicate Emission in Young Brown Dwarfs
We present mid-infrared photometry of three very young brown dwarfs located
in the Ophiuchi star-forming region -- GY5, GY11 and GY310 --obtained
with the Subaru 8-meter telescope. All three sources were detected at 8.6 and
11.7m, confirming the presence of significant mid-infrared excess arising
from optically thick dusty disks. The spectral energy distributions of both
GY310 and GY11 exhibit strong evidence of flared disks; flat disks can be ruled
out for these two brown dwarfs. The data for GY5 show large scatter, and are
marginally consistent with both flared and flat configurations. Inner holes a
few substellar radii in size are indicated in all three cases (and especially
in GY11), in agreement with magnetospheric accretion models. Finally, our
9.7m flux for GY310 implies silicate emission from small grains on the
disk surface (though the data do not completely preclude larger grains with no
silicate feature). Our results demonstrate that disks around young substellar
objects are analogous to those girdling classical T Tauri stars, and exhibit a
similar range of disk geometries and dust properties.Comment: submitted to Astrophysical Journal Letter
Glial Cell Lineage Expression of Mutant Ataxin-1 and Huntingtin Induces Developmental and Late-Onset Neuronal Pathologies in Drosophila Models
In several neurodegenerative disorders, toxic effects of glial cells on neurons are implicated. However the generality of the non-cell autonomous pathologies derived from glial cells has not been established, and the specificity among different neurodegenerative disorders remains unknown.We newly generated Drosophila models expressing human mutant huntingtin (hHtt103Q) or ataxin-1 (hAtx1-82Q) in the glial cell lineage at different stages of differentiation, and analyzed their morphological and behavioral phenotypes. To express hHtt103Q and hAtx1-82Q, we used 2 different Gal4 drivers, gcm-Gal4 and repo-Gal4. Gcm-Gal4 is known to be a neuroglioblast/glioblast-specific driver whose effect is limited to development. Repo-Gal4 is known to be a pan-glial driver and the expression starts at glioblasts and continues after terminal differentiation. Gcm-Gal4-induced hHtt103Q was more toxic than repo-Gal4-induced hHtt103Q from the aspects of development, locomotive activity and survival of flies. When hAtx1-82Q was expressed by gcm- or repo-Gal4 driver, no fly became adult. Interestingly, the head and brain sizes were markedly reduced in a part of pupae expressing hAtx1-82Q under the control of gcm-Gal4, and these pupae showed extreme destruction of the brain structure. The other pupae expressing hAtx1-82Q also showed brain shrinkage and abnormal connections of neurons. These results suggested that expression of polyQ proteins in neuroglioblasts provided a remarkable effect on the developmental and adult brains, and that glial cell lineage expression of hAtx1-82Q was more toxic than that of hHtt103Q in our assays.All these studies suggested that the non-cell autonomous effect of glial cells might be a common pathology shared by multiple neurodegenerative disorders. In addition, the fly models would be available for analyzing molecular pathologies and developing novel therapeutics against the non-cell autonomous polyQ pathology. In conclusion, our novel fly models have extended the non-cell autonomous pathology hypothesis as well as the developmental effect hypothesis to multiple polyQ diseases. The two pathologies might be generally shared in neurodegeneration
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