154 research outputs found

    Spatial Dependence, Social Networks, and Economic Structures in Regional Labor Migration

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    This study empirically analyzes the determinants of regional labor migration in Japan, where small towns are disappearing due to the shortage of labor. Using spatial models of origin-destination flows and considering network effects of labor and economic structures, we obtain results more consistent with the standard migration theory than previous studies. First, unlike previous studies, we find that migration decisions in Japan are based on economic motivations consistent with economic theories. Particularly, unemployment rates in origins and destinations and income in origins are found to be the determinants of labor migration. Second, we report that network effects, which help reduce migration costs, have encouraged relocation of labor. Third, considering spatial weights based on distance, goods flow, and economic structures, we show that neighbors can be most appropriately defined with economic structures; migration patterns are alike in regions with similar economic structures

    Detection of Polarized Broad Emission in the Seyfert 2 Galaxy Mrk 573

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    We report the discovery of the scattered emission from a hidden broad-line region (BLR) in a Seyfert 2 galaxy, Mrk 573, based on our recent spectropolarimetric observation performed at the Subaru Telescope. This object has been regarded as a type 2 AGN without a hidden BLR by the previous observations. However, our high quality spectrum of the polarized flux of Mrk 573 shows prominent broad (~3000 km/s) H_alpha emission, broad weak H_beta emission, and subtle Fe II multiplet emission. Our new detection of these indications for the presence of the hidden BLR in the nucleus of Mrk 573 is thought to be owing to the high signal-to-noise ratio of our data, but the possibility of a time variation of the scattered BLR emission is also mentioned. Some diagnostic quantities such as the IRAS color, the radio power, and the line ratio of the emission from the narrow-line region of Mrk 573 are consistent with the distributions of such quantities of type 2 AGNs with a hidden BLR. Mrk 573 is thought to be an object whose level of the AGN activity is the weakest among the type 2 AGNs with a hidden BLR. In terms of the systematic differences between the type 2 AGNs with and without a hidden BLR, we briefly comment on an interesting Seyfert 2 galaxy, Mrk 266SW, which may possess a hidden BLR but has been treated as a type 2 AGNs without a hidden BLR.Comment: 9 pages including 6 figures, to appear in The Astronomical Journa

    Microsatellite loci in Japanese quail and�cross-species amplification in�chicken and�guinea fowl

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    In line with the Gifu University's initiative to map the Japanese quail genome, a total of 100 Japanese quail microsatellite markers isolated in our laboratory were evaluated in a population of 20 unrelated quails randomly sampled from a colony of wild quail origin. Ninety-eight markers were polymorphic with an average of 3.7 alleles per locus and a mean heterozygosity of 0.423. To determine the utility of these markers for comparative genome mapping in Phasianidae, cross-species amplification of all the markers was tested with chicken and guinea fowl DNA. Amplification products similar in size to the orthologous loci in quail were observed in 42 loci in chicken and 20 loci in guinea fowl. Of the cross-reactive markers, 57.1% in chicken and 55.0% in guinea fowl were polymorphic when tested in 20 birds from their respective populations. Five of 15 markers that could cross-amplify Japanese quail, chicken, and guinea fowl DNA were polymorphic in all three species. Amplification of orthologous loci was confirmed by sequencing 10 loci each from chicken and guinea fowl and comparing with them the corresponding quail sequence. The microsatellite markers reported would serve as a useful resource base for genetic mapping in quail and comparative mapping in Phasianidae

    SDSSp J104433.04-012502.2 at z=5.74z=5.74 is Gravitationally Magnified by an Intervening Galaxy

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    During the course of our optical deep survey program on Lα\alpha emitters at z5.7z \approx 5.7 in the sky area surrounding the quasar SDSSp J104433.04-012502.2 at z=5.74z=5.74, we found that a faint galaxy with mBm_B(AB) 25\approx 25 is located at \timeform{1".9} southwest of the quasar. Its broad-band color properties from BB to zz^\prime suggest that the galaxy is located at a redshift of z1.5z \sim 1.5 -- 2.5. This is consistent with no strong emission line in our optical spectroscopy. Since the counter image of the quasar cannot be seen in our deep optical images, the magnification factor seems not to be very high. Our modest estimate is that this quasar is gravitationally magnified by a factor of 2.Comment: 11 pages, 5 figures, PASJ, in pres

    On the Origin of Lyman-α\alpha Blobs at High Redshift: Kinematic Evidence for a Hyperwind Galaxy at z = 3.1

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    We present deep optical spectroscopy of an extended Lyα\alpha emission-line blob located in an over-dense region at redshift z3.1z \approx 3.1; `blob 1' of Steidel et al. (2000). The origin of such Lyα\alpha blobs has been debated for some time; two of the most plausible models are (1) that it comes from a dust-enshrouded, extreme starburst galaxy with a large-scale galactic outflow (superwind/hyperwind) or (2) that it is the cooling radiation of proto-galaxies in dark matter halos. Examination of the kinematic properties of the Lyα\alpha emission-line gas should allow us to determine its nature. With this motivation, we performed optical spectroscopy of `blob 1' using the Subaru Telescope, and found that its kinematic properties can be well explained in terms of superwind activity.Comment: 12 pages, including 4 figures, accepted for publication in ApJ

    Co-morbidity of progressive supranuclear palsy and amyotrophic lateral sclerosis : a clinical-pathological case report

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    Background: The coexistence of distinct neurodegenerative diseases in single cases has recently attracted greater attention. The phenotypic co-occurrence of progressive supranuclear palsy (PSP) and amyotrophic lateral sclerosis (ALS) has been documented in several cases. That said, the clinicopathological comorbidity of these two diseases has not been demonstrated. Case presentation: A 77-year-old man presented with gait disturbance for 2 years, consistent with PSP with progressive gait freezing. At 79 years old, he developed muscle weakness compatible with ALS. The disease duration was 5 years after the onset of PSP and 5months after the onset of ALS. Neuropathological findings demonstrated the coexistence of PSP and ALS. Immunohistochemical examination confirmed 4-repeat tauopathy, including globose-type neurofibrillary tangles, tufted astrocytes, and oligodendroglial coiled bodies as well as TAR DNA-binding protein 43 kDa pathology in association with upper and lower motor neuron degeneration. Immunoblotting showed hyperphosphorylated full-length 4-repeat tau bands (64 and 68 kDa) and C-terminal fragments (33 kDa), supporting the diagnosis of PSP and excluding other parkinsonian disorders, such as corticobasal degeneration. Genetic studies showed no abnormalities in genes currently known to be related to ALS or PSP. Conclusions: Our case demonstrates the clinicopathological comorbidity of PSP and ALS in a sporadic patient. The possibility of multiple proteinopathies should be considered when distinct symptoms develop during the disease course
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