40 research outputs found
大脳視覚情報処理に基づく神経振動と曲率表現を用いた物体認識のモデル化に関する研究
Tohoku University佐藤茂雄課
Large Population of ALMA Galaxies at z>6 with Very High [OIII]88um to [CII]158um Flux Ratios: Evidence of Extremely High Ionization Parameter or PDR Deficit?
We present our new ALMA observations targeting [OIII]88um, [CII]158um,
[NII]122um, and dust continuum emission for three Lyman break galaxies at
z=6.0293-6.2037 identified in the Subaru/Hyper Suprime-Cam survey. We clearly
detect [OIII] and [CII] lines from all of the galaxies at 4.3-11.8sigma levels,
and identify multi-band dust continuum emission in two of the three galaxies,
allowing us to estimate infrared luminosities and dust temperatures
simultaneously. In conjunction with previous ALMA observations for six galaxies
at z>6, we confirm that all the nine z=6-9 galaxies have high [OIII]/[CII]
ratios of L[OIII]/L[CII]~3-20, ~10 times higher than z~0 galaxies. We also find
a positive correlation between the [OIII]/[CII] ratio and the Lya equivalent
width (EW) at the ~90% confidence level. We carefully investigate physical
origins of the high [OIII]/[CII] ratios at z=6-9 using Cloudy, and find that
high density of the interstellar medium, low C/O abundance ratio, and the
cosmic microwave background attenuation are responsible to only a part of the
z=6-9 galaxies. Instead, the observed high [OIII]/[CII] ratios are explained by
10-100 times higher ionization parameters or low photodissociation region (PDR)
covering fractions of 0-10%, both of which are consistent with our [NII]
observations. The latter scenario can be reproduced with a density bounded
nebula with PDR deficit, which would enhance the Lya, Lyman continuum, and C+
ionizing photons escape from galaxies, consistent with the [OIII]/[CII]-Lya EW
correlation we find.Comment: 20 pages, 18 figures, Accepted for publication in Ap
Gas Motion Study of Lya Emitters at z~2 Using UV and Optical Spectral Lines
We present the results of Magellan/MMIRS and Keck/NIRSPEC spectroscopy for
five Lya emitters (LAEs) at z=2.2 for which high-resolution FUV spectra from
Magellan/MagE are available. We detect nebular emission lines including Ha on
the individual basis and low-ionization interstellar (LIS) absorption lines in
a stacked FUV spectrum, and measure average offset velocities of the Lya line,
Delta_v_Lya, and LIS absorption lines, Delta_v_abs, with respect to the
systemic velocity defined by the nebular lines. For a sample of eight z~2-3
LAEs without AGN from our study and the literature, we obtain Delta_v_Lya =
175+/-35 km s^{-1}, which is significantly smaller than that of Lyman-break
Galaxies (LBGs), Delta_v_Lya=400 km s^{-1}. The stacked FUV spectrum gives
Delta_v_abs = -179 +/- 73 km s^{-1}, comparable to that of LBGs. These positive
Delta_v_Lya and negative Delta_v_abs suggest that LAEs also have outflows. In
contrast to LBGs, however, the LAEs' Delta_v_Lya is as small as |Delta_v_abs|,
suggesting low neutral hydrogen column densities. Such a low column density
with a small number of resonant scattering may cause the observed strong Lya
emission of LAEs. We find an anti-correlation between Lya equivalent width (EW)
and Delta_v_Lya in a compilation of LAE and LBG samples. Although its physical
origin is not clear, this anti-correlation result appears to challenge the
hypothesis that a strong outflow, by means of a reduced number of resonant
scattering, produces a large EW. If LAEs at z>6 have similarly small
Delta_v_Lya values, constraints on the reionization history derived from the
Lya transmissivity may need to be revised.Comment: 15 pages, 13 figures, 7 tables. Accepted for publication in Ap
Dissociation of Tau Deposits and Brain Atrophy in Early Alzheimer’s Disease: A Combined Positron Emission Tomography/Magnetic Resonance Imaging Study
The recent advent of tau-specific positron emission tomography (PET) has enabled in vivo assessment of tau pathology in Alzheimer’s disease (AD). However, because PET scanners have limited spatial resolution, the measured signals of small brain structures or atrophied areas are underestimated by partial volume effects (PVEs). The aim of this study was to determine whether partial volume correction (PVC) improves the precision of measures of tau deposits in early AD. We investigated tau deposits in 18 patients with amyloid-positive early AD and in 36 amyloid-negative healthy controls using 18F-THK5351 PET. For PVC, we applied the SPM toolbox PETPVE12. The PET images were then spatially normalized and subjected to voxel-based group analysis using SPM12 for comparison between the early AD patients and healthy controls. We also compared these two groups in terms of brain atrophy using voxel-based morphometry of MRI. We found widespread neocortical tracer retention predominantly in the posterior cingulate and precuneus areas, but also in the inferior temporal lobes, inferior parietal lobes, frontal lobes, and occipital lobes in the AD patients compared with the controls. The pattern of tracer retention was similar between before and after PVC, suggesting that PVC had little effect on the precision of tau load measures. Gray matter atrophy was detected in the medial/lateral temporal lobes and basal frontal lobes in the AD patients. Interestingly, only a few associations were found between atrophy and tau deposits, even after PVC. In conclusion, PVC did not significantly affect 18F-THK5351 PET measures of tau deposits. This discrepancy between tau deposits and atrophy suggests that tau load precedes atrophy
DOCK2 is involved in the host genetics and biology of severe COVID-19
「コロナ制圧タスクフォース」COVID-19疾患感受性遺伝子DOCK2の重症化機序を解明 --アジア最大のバイオレポジトリーでCOVID-19の治療標的を発見--. 京都大学プレスリリース. 2022-08-10.Identifying the host genetic factors underlying severe COVID-19 is an emerging challenge. Here we conducted a genome-wide association study (GWAS) involving 2, 393 cases of COVID-19 in a cohort of Japanese individuals collected during the initial waves of the pandemic, with 3, 289 unaffected controls. We identified a variant on chromosome 5 at 5q35 (rs60200309-A), close to the dedicator of cytokinesis 2 gene (DOCK2), which was associated with severe COVID-19 in patients less than 65 years of age. This risk allele was prevalent in East Asian individuals but rare in Europeans, highlighting the value of genome-wide association studies in non-European populations. RNA-sequencing analysis of 473 bulk peripheral blood samples identified decreased expression of DOCK2 associated with the risk allele in these younger patients. DOCK2 expression was suppressed in patients with severe cases of COVID-19. Single-cell RNA-sequencing analysis (n = 61 individuals) identified cell-type-specific downregulation of DOCK2 and a COVID-19-specific decreasing effect of the risk allele on DOCK2 expression in non-classical monocytes. Immunohistochemistry of lung specimens from patients with severe COVID-19 pneumonia showed suppressed DOCK2 expression. Moreover, inhibition of DOCK2 function with CPYPP increased the severity of pneumonia in a Syrian hamster model of SARS-CoV-2 infection, characterized by weight loss, lung oedema, enhanced viral loads, impaired macrophage recruitment and dysregulated type I interferon responses. We conclude that DOCK2 has an important role in the host immune response to SARS-CoV-2 infection and the development of severe COVID-19, and could be further explored as a potential biomarker and/or therapeutic target
Wide Area Ray-Launching for Pilot Pollution Analyses using Adaptive Object Selection
Abstract: We propose a new method of ray-launching estimation for high-speed and highly accurate analysis of pilot pollution, which often occurs in the upper floors of high-rise buildings. Our method simulates radio signals that reach from distant base stations much faster than a conventional raylaunching method. The mechanism of the fast calculation is due to an adaptive object selection approach, which excludes objects that have limited effects on a radio environment in the upper floors of high-rise buildings. It is confirmed that our method can make a calculation more than 20 times faster than a conventional ray-launching method with almost the same accuracy for the case with high base station antennas
Comparative Targeted Proteomics of the Central Metabolism and Photosystems in SigE Mutant Strains of Synechocystis sp. PCC 6803
A targeted proteome analysis was conducted to investigate the SigE dependent-regulation of central metabolism in Synechocystis sp. PCC 6803 by directly comparing the protein abundance profiles among the wild type, a sigE deletion mutant (ΔsigE), and a sigE over-expression (sigEox) strains. Expression levels of 112 target proteins, including the central metabolism related-enzymes and the subunits of the photosystems, were determined by quantifying the tryptic peptides in the multiple reaction monitoring (MRM) mode of liquid-chromatography–triple quadrupole mass spectrometry (LC–MS/MS). Comparison with gene-expression data showed that although the abundance of Gnd protein was closely correlated with that of gnd mRNA, there were poor correlations for GdhA/gdhA and glycogen degradation-related genes such as GlgX/glgX and GlgP/glgP pairs. These results suggested that the regulation of protein translation and degradation played a role in regulating protein abundance. The protein abundance profile suggested that SigE overexpression reduced the proteins involved in photosynthesis and increased GdhA abundance, which is involved in the nitrogen assimilation pathway using NADPH. The results obtained in this study successfully demonstrated that targeted proteome analysis enables direct comparison of the abundance of central metabolism- and photosystem-related proteins