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857 result(s) for "Takahashi, Kosuke"
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BEACON: JWST NIRCam Pure-parallel Imaging Survey. I. Survey Design and Initial Results
We introduce the Bias-free Extragalactic Analysis for Cosmic Origins with NIRCam (BEACON) survey, a JWST Cycle 2 program allocated up to 600 pure-parallel hours of observations. BEACON explores high-latitude areas of the sky with JWST/NIRCam over ∼100 independent sight lines, totaling ∼0.3 deg2, reaching a median F444W depth of ≈28.2 AB mag (5σ). Based on existing JWST observations in legacy fields, we estimate that BEACON will photometrically identify 25–150 galaxies at z > 10 and 500–1000 at z ∼ 7–10 uniquely enabled by an efficient multiple filter configuration spanning 0.9–5.0 μm. The expected sample size of z > 10 galaxies will allow us to obtain robust number density estimates and to discriminate between different models of early star formation. In this paper, we present an overview of the survey design and initial results using the first 19 fields. We present 129 galaxy candidates at z ≳7 identified in those fields, including 11 galaxies at z ≳10 and several UV-luminous (MUV < −21 mag) galaxies at z ∼ 8. The number densities of z < 13 galaxies inferred from the initial fields are overall consistent with those in the literature. Despite reaching a considerably large volume (∼105 Mpc3), however, we find no galaxy candidates at z > 13, providing us with a complimentary insight into early galaxy evolution with minimal cosmic variance. We publish imaging and catalog data products for these initial fields. Upon survey completion, all BEACON data will be coherently processed and distributed to the community along with catalogs for redshift and other physical quantities.
Factors affecting foveal avascular zone in healthy eyes: An examination using swept-source optical coherence tomography angiography
To examine factors affecting foveal avascular zone (FAZ) area in healthy eyes using swept-source optical coherence tomography angiography (OCTA). This prospective, cross-sectional study included 144 eyes of 144 individuals (77 women, 67 men) with a best corrected visual acuity of at least 20/20 and no history of ocular disorders. The area of the superficial FAZ was assessed using OCTA. Age, gender, central retinal thickness (CRT), retinal vascular density, refractive error, and axial length were examined to determine associations with FAZ area. The mean age of the subjects was 42.1 ± 20.2 years (range: 10-79 years). The mean FAZ area was 0.32 ± 0.11 mm2, while the mean retinal vascular density was 35.53 ± 0.92%. Multivariate regression analysis was performed using FAZ area as the dependent variable and age, gender, CRT, retinal vascular density, refractive error, and axial length as independent variables. The results of this analysis demonstrate that CRT and retinal vascular density were significantly associated with FAZ area in our sample (P < 0.001, R2 = 0.425). Age, gender, refractive error, and axial length were not significantly correlated with FAZ area, while CRT and retinal vascular density were negatively correlated with FAZ area (CRT: P < 0.001, R2 = 0.356; retinal vascular density: P < 0.001, R2 = 0.189). OCTA results suggest that CRT and retinal vascular density negatively affect FAZ area in healthy eyes.
Discovery of an X-Ray Luminous Radio-loud Quasar at z = 3.4: A Possible Transitional Super-Eddington Phase
We report the multiwavelength properties of eROSITA Final Equatorial Depth Survey (eFEDS) J084222.9+001000 (hereafter ID830), a quasar at z = 3.4351, identified as the most X-ray luminous radio-loud quasar in the eFEDS field. ID830 shows a rest-frame 0.5–2 keV luminosity of log(L0.5−2keV/ergs−1)=46.20±0.12 , with a steep X-ray photon index (Γ = 2.43 ± 0.21), and a significant radio counterpart detected with the Very Large Array FIRST 1.4 GHz and Very Large Array Sky Survey 3 GHz bands. The rest-frame UV to optical spectra from Sloan Digital Sky Survey and Subaru/MOIRCS J band show a dust-reddened quasar feature with AV = 0.39 ± 0.08 mag, and the expected bolometric active galactic nuclei luminosity from the dust-extinction-corrected UV luminosity reaches Lbol,3000Å = (7.62 ± 0.31) × 1046 erg s−1. We estimate a black hole mass of MBH = (4.40 ± 0.72) × 108 M⊙ based on the Mg IIλ2800 emission-line width, and Eddington ratios from the dust-extinction-corrected UV continuum luminosity and X-ray luminosity that reach λEdd,UV = 1.44 ± 0.24 and λEdd,X = 12.8 ± 3.9, respectively, both indicating super-Eddington accretion. ID830 shows a high ratio of UV to X-ray luminosities, αOX = −1.20 ± 0.07 (or αOX = −1.42 ± 0.07 after correcting for jet-linked X-ray excess), higher than quasars and little red dots in the super-Eddington phase with similar UV luminosities, with αOX < −1.8. Such a high αOX suggests the coexistence of a prominent radio jet and X-ray corona in this high-Eddington-accretion phase. We propose that ID830 may be in a transitional phase after an accretion burst, evolving from a super-Eddington to a sub-Eddington state, which could naturally describe the high αOX.
Which is the Better Inpainted Image?Training Data Generation Without Any Manual Operations
This paper proposes a learning-based quality evaluation framework for inpainted results that does not require any subjectively annotated training data. Image inpainting, which removes and restores unwanted regions in images, is widely acknowledged as a task whose results are quite difficult to evaluate objectively. Thus, existing learning-based image quality assessment (IQA) methods for inpainting require subjectively annotated data for training. However, subjective annotation requires huge cost and subjects’ judgment occasionally differs from person to person in accordance with the judgment criteria. To overcome these difficulties, the proposed framework generates and uses simulated failure results of inpainted images whose subjective qualities are controlled as the training data. We also propose a masking method for generating training data towards fully automated training data generation. These approaches make it possible to successfully estimate better inpainted images, even though the task is quite subjective. To demonstrate the effectiveness of our approach, we test our algorithm with various datasets and show it outperforms existing IQA methods for inpainting.
Results of lamellar macular hole-associated epiretinal proliferation embedding technique for the treatment of degenerative lamellar macular hole
PurposeTo investigate the outcomes of embedding lamellar hole-associated epiretinal proliferation (LHEP) into retinal cleavage for the surgical treatment of degenerative lamellar macular hole (LMH).MethodsWe retrospectively reviewed the medical records of 34 consecutive eyes of degenerative LMH patients who underwent vitrectomy with LHEP embedding and who were followed up for at least 12 months. Best-corrected visual acuity (BCVA), central retinal thickness (CRT), and macular structure preoperatively and at the final follow-up were compared.ResultsThe mean (±SD) follow-up period was 30.0 ± 17.7 months. Twelve patients (35.3%) were men, and the mean age was 69.6 ± 10.1 years. Twenty-three eyes (67.6%) underwent simultaneous cataract surgery. BCVA was significantly improved at the final visit, from 0.31 ± 0.25 logarithm of the minimum angle of resolution units to 0.10 ± 0.25 (P < 0.01). This improvement in mean BCVA at the final postoperative visit occurred regardless of whether the eyes underwent simultaneous cataract surgery, from 0.30 ± 0.26 preoperatively to 0.04 ± 0.16 (P < 0.01) in the “with cataract surgery” group and from 0.32 ± 0.26 preoperatively to 0.21 ± 0.35 (P < 0.05) in the “without cataract surgery” group. CRT was also significantly improved at the final visit, from 123.2 ± 42.6 μm preoperatively to 191.2 ± 42.6 μm (P < 0.01). External limiting membrane and ellipsoid zone defects were detected in 17 (50.0%) and 15 (44.1%) eyes, respectively, but these were resolved in 10 (58.8%) and 7 (46.7%) eyes, respectively, at the final visit. No intraoperative or postoperative complications were observed.ConclusionsEmbedding LHEP may be an effective and safe procedure to treat degenerative LMH.
X-ray nanoimaging of a transversely embedded carbon fiber in epoxy matrix under static and cyclic loads
The initial stage of fatigue failure has not been thoroughly clarified for carbon fiber reinforced plastics (CFRPs). Although the initiation of fatigue cracks has been regarded to be interfacial debonding between the carbon fiber and polymer matrix, their detection among numerous carbon fibers, whose diameter is only 7 µm, is extremely difficult. In this study, a single carbon fiber was transversely embedded in a dumbbell-shaped epoxy sample to focus on the interfacial debonding and was observed using synchrotron radiation (SR) X-ray computed tomography (CT). A tabletop fatigue testing machine driven by a piezoelectric actuator was developed to apply static and cyclic loads along the beamline. SR X-ray multiscale CT imaging was conducted by switching between an absorption-contrast projection method (micro-CT) and a phase-contrast imaging-type X-ray microscopic CT (nano-CT). The carbon fiber was entirely captured by micro-CT and then magnified at both ends on the free surfaces. Nano-CT clearly visualized the interfacial debonding under 30 MPa static tensile load and the implication of the coalescence of nano-voids along the interface under 50 MPa. Under cyclic loads, the interfacial debonding gradually progressed under a 8–40 MPa sinusoidal stress after 10,000 cycles, whereas it did not propagate under a stress below 30 MPa.
Output Control of Three-Axis PMSG Wind Turbine Considering Torsional Vibration Using H Infinity Control
Due to changes in wind, the torque obtained from the wind turbine always fluctuates. Here, the wind turbine and the rotor of the generator are connected by a shaft that is one elastic body, and each rotating body has different inertia. The difference in inertia between the wind turbine and the generator causes a torsion between the wind generator and the generator; metal fatigue and torsion can damage the shaft. Therefore, it is necessary to consider the axial torsional vibration suppression of a geared wind power generator using a permanent magnet synchronous generator (PMSG). In addition, errors in axis system parameters occur due to long-term operation of the generator, and it is important to estimate for accurate control. In this paper, we propose torque estimation using H ∞ observer and axial torsional vibration suppression control in a three inertia system. The H ∞ controller is introduced into the armature current control system (q-axis current control system) of the wind power generator. Even if parameter errors and high-frequency disturbances are included, the shaft torsional torque is estimated by the H ∞ observer that can perform robust estimation. Moreover, by eliminating the resonance point of the shaft system, vibration suppression of the shaft torsional torque is achieved. The results by the proposed method can suppress axial torsional vibration and show the effect better than the results using Proportional-Integral (PI) control.
Characterizing alcohol-related and metabolic dysfunction-associated steatotic liver disease cirrhosis via fibrotic pattern analysis
This study aimed to address the diagnostic challenges in distinguishing between alcohol-related liver disease (ALD) and metabolic dysfunction-associated steatotic liver disease (MASLD). We utilized whole-slide imaging technology to conduct a comprehensive digital analysis of liver specimens collected from patients undergoing transplantation. This study included 36 and 17 patients with ALD and MASLD cirrhosis, respectively, who underwent transplantation at our institution. Digital slides were analyzed for fibrosis patterns using FibroNest™. Patient background characteristics were comparable between ALD ( n  = 36) and MASLD ( n  = 17) groups, except for sex. The ALD group exhibited thicker collagen per strand, longer and more flexural fibrosis, and a more heterogeneous distribution than the MASLD group. In patients with ALD and concomitant metabolic dysfunction, fiber distribution became relatively uniform, resembling MASLD. Application of the phenotypic fibrosis composite score achieved 100% sensitivity and specificity for ALD/MASLD diagnosis. Digital pathological analysis of the fibrosis patterns showed morphological differences between ALD and MASLD. This approach holds promise for histological differentiation, providing valuable insights beyond the current definitions based solely on alcohol intake. This study emphasizes the potential of digital pathology in refining the diagnostic criteria for hepatic disorders.
Elevated intestinal fatty acid-binding protein levels as a marker of portal hypertension and gastroesophageal varices in cirrhosis
We measured intestinal fatty acid-binding protein (I-FABP) levels, a useful marker of small intestinal mucosal injury, in patients with cirrhosis to determine their relationship with liver function and complications. This cross-sectional study included 71 patients with cirrhosis admitted for treatment of cirrhotic complications or hepatocellular carcinoma (cohort A) and 104 patients with cirrhosis who received direct-acting antiviral therapy for HCV (cohort B). I-FABP levels, measured by ELISA, were evaluated relative to hepatic reserve and compared with non-invasive scoring systems for diagnostic performance in cirrhotic complications. The median I-FABP level in both cohorts were significantly elevated in patients with reduced hepatic reserve (CTP grade A/BC cohort A, 2.33/3.17 ng/mL, p  = 0.032; cohort B, 2.46/3.64 ng/mL, p  = 0.008) and complications with gastroesophageal varices (GEV; GEV (-)/(+) cohort A, 1.66/3.67 ng/mL, p  < 0.001; cohort B, 2.32/3.36 ng/mL; p  = 0.003). Further, multiple logistic regression analysis identified I-FABP as the only factor contributing to GEV presence in both cohorts, which outperformed non-invasive scoring systems for GEV diagnosis (sensitivity 84.6%; specificity 84.2%; sensitivity 69.6%; specificity 63.8%, respectively). In conclusion, elevated small-intestinal mucosal injury in patients with cirrhosis was related to reduced hepatic reserve and GEV presence. I-FABP levels reflect portal hypertension and may be useful in cirrhosis management.
En face image-based classification of diabetic macular edema using swept source optical coherence tomography
This retrospective study was performed to classify diabetic macular edema (DME) based on the localization and area of the fluid and to investigate the relationship of the classification with visual acuity (VA). The fluid was visualized using en face optical coherence tomography (OCT) images constructed using swept-source OCT. A total of 128 eyes with DME were included. The retina was segmented into: Segment 1, mainly comprising the inner nuclear layer and outer plexiform layer, including Henle’s fiber layer; and Segment 2, mainly comprising the outer nuclear layer. DME was classified as: foveal cystoid space at Segment 1 and no fluid at Segment 2 (n = 24), parafoveal cystoid space at Segment 1 and no fluid at Segment 2 (n = 25), parafoveal cystoid space at Segment 1 and diffuse fluid at Segment 2 (n = 16), diffuse fluid at both segments (n = 37), and diffuse fluid at both segments with subretinal fluid (n = 26). Eyes with diffuse fluid at Segment 2 showed significantly poorer VA, higher ellipsoid zone disruption rates, and greater central subfield thickness than did those without fluid at Segment 2 ( P  < 0.001 for all). These results indicate the importance of the localization and area of the fluid for VA in DME.