Explanipedia

Identification and characterization of nascent planetary nebulae with OH and H 2 O masers Open

Roldán A. Cala, José F. Gómez, L. F. Miranda, Hiroshi Imai, Guillem Anglada , et al. · 2025

Stars such as the Sun expel their outer layers and form planetary nebulae (PNe) as they evolve into white dwarfs. PNe exhibit diverse morphologies, the origins of which are not fully understood. PNe with OH (OHPNe) and H 2 O (H 2 OPNe) mas…

Identification and characterization of nascent planetary nebulae with OH and H$_2$O masers Open

Roldán A. Cala, José F. Gómez, L. F. Miranda, Hiroshi Imai, Guillem Anglada , et al. · 2025

Stars like the Sun expel their outer layers and form planetary nebulae (PNe) as they evolve into white dwarfs. PNe exhibit diverse morphologies, the origins of which are not fully understood. PNe with OH (OHPNe) and H$_{2}$O (H$_{2}$OPNe) …

SiO v = 1 J = 5 → 4 Maser Emission from the Root of the “Water Fountain” Source W 43A Open

Hiroshi Imai, T. Hoshino, Daniel Tafoya, José F. Gómez, Jun‐ichi Nakashima , et al. · 2025

We report here the first mapping of SiO v = 1 J = 5 → 4 maser emission toward the “water fountain” source W 43A in order to explore the central stellar system driving the collimated, bipolar, fast jet. The maser source has a systemic line-…

The Nearby Evolved Stars Survey (NESS) V: properties of volume-limited samples of Galactic evolved stars Open

Iain McDonald, S. Srinivasan, Peter Scicluna, Olivia Jones, A. A. Zijlstra , et al. · 2025

We provide a meta-study of the statistical and individual properties of two volume-complete sets of evolved stars in the solar neighbourhood: (1) 852 stars from the Nearby Evolved Stars Survey (NESS), and (2) a partially overlapping set of…

First VLBI imaging of SiO v = 0, J = 1→0 masers in VY Canis Majoris Open

Hiroko Shinnaga, Miyako Oyadomari, Hiroshi Imai, Tomoaki Oyama, M. J. Claussen , et al. · 2025

We have achieved the first VLBI detections of the ground vibrational state (v = 0) 28SiO (hereafter, SiO) and 29SiO masers of the J = 1→0 rotational transitions, towards the 25 $M_{\odot }$ red supergiant (RSG) star, VY Canis Majoris (VY C…

ALMA observations of CO isotopologues towards six obscured post-asymptotic giant branch stars Open

T. Khouri, Daniel Tafoya, W. H. T. Vlemmings, H. Olofsson, C. Sánchez Contreras , et al. · 2025

Context. Low- and intermediate-mass stars evolve through the asymptotic giant branch (AGB) when an efficient mass-loss process removes a significant fraction of their initial mass. For most sources, this mass-loss process relies on the int…

ALMA observations of CO isotopologues towards six obscured post-AGB stars Open

T. Khouri, Daniel Tafoya, W. H. T. Vlemmings, H. Olofsson, C. Sánchez Contreras , et al. · 2025

Low- and intermediate-mass stars evolve through the asymptotic giant branch (AGB), when an efficient mass-loss process removes a significant fraction of their initial mass. A substantial increase in the mass-loss rate at the end of the AGB…

Time‐dependent MR diffusion analysis of functioning and nonfunctioning pituitary adenomas/pituitary neuroendocrine tumors Open

Kiyohisa Kamimura, Tetsuo TOKUDA, Junki Kamizono, Tsubasa Nakano, Tomohito Hasegawa , et al. · 2024

Background and Purpose Differentiation between functioning and nonfunctioning pituitary adenomas/pituitary neuroendocrine tumors (PAs) is clinically relevant. The goal of this study was to determine the feasibility of using time‐dependent …

An interferometric search for SiO maser emission in planetary nebulae Open

Roldán A. Cala, José F. Gómez, L. F. Miranda, Hiroshi Imai, I. de Gregorio‐Monsalvo , et al. · 2024

Maser emission of SiO, H$_2$O and, OH is widespread in Asymptotic Giant Branch (AGB) stars with oxygen(O)-rich envelopes. This emission quickly disappear during the post-AGB phase and is extremely rare in planetary nebulae (PN). So far, on…

An interferometric search for SiO maser emission in planetary nebulae Open

Roldán A. Cala, José F. Gómez, L. F. Miranda, Hiroshi Imai, I. de Gregorio‐Monsalvo , et al. · 2024

Context. Maser emission of SiO, H 2 O, and OH is widespread in asymptotic giant branch (AGB) stars with oxygen- (O-) rich envelopes. This emission quickly disappears during the post-AGB phase and is extremely rare in planetary nebulae (PNe…

Trigonometric parallax and proper motion of Sagittarius A* measured by VERA using the new broad-band back-end system OCTAVE-DAS Open

Tomoaki Oyama, Takumi Nagayama, Aya Yamauchi, Daisuke Sakai, Hiroshi Imai , et al. · 2024

We successfully measured the trigonometric parallax of Sagittarius A* (Sgr A*) to be 117 ± 17 micro-arcseconds ($\, \mu \mbox{as}$) using the VLBI Exploration of Radio Astrometry (VERA) with the newly developed broad-band signal-processing…

Systematic Search for Water Fountain Candidates Using the Databases of Circumstellar Maser Sources Open

Haichen 海辰 Fan 范, Jun‐ichi Nakashima, D. Engels, Yong Zhang, Jianjie Qiu , et al. · 2024

Water fountains (WFs) are thought to be objects in the morphological evolution of the circumstellar envelopes of low- and intermediate-mass evolved stars, transitioning from spherically symmetric to asymmetric shapes. We used databases of …

Differentiating primary central nervous system lymphoma from glioblastoma by time-dependent diffusion using oscillating gradient Open

Kiyohisa Kamimura, Tsubasa Nakano, Tomohito Hasegawa, Masanori Nakajo, Chihiro Yamada , et al. · 2023

Background This study aimed to elucidate the impact of effective diffusion time setting on apparent diffusion coefficient (ADC)-based differentiation between primary central nervous system lymphomas (PCNSLs) and glioblastomas (GBMs) and to…

Systematic Search for Water Fountain Candidates using the Databases of Circumstellar Maser Sources Open

Haichen Fan, Jun‐ichi Nakashima, D. Engels, Yong Zhang, Jianjie Qiu , et al. · 2023

Water fountains (WFs) are thought to be objects in the morphological evolution of the circumstellar envelopes of low- and intermediate-mass evolved stars, transitioning from spherically symmetric to asymmetric shapes. We used databases of …

FLASHING: Project overview Open

Hiroshi Imai, Yuhki Hamae, Kei Amada, Keisuke Nakashima, Ka-Yiu Shum , et al. · 2023

This paper describes an overview of the FLASHING (Finest Legacy Acquisitions of SiO-/H2O-maser Ignitions by the Nobeyama Generation) project promoted using the 45 m telescope of Nobeyama Radio Observatory, which aims to intensively monitor…

FLASHING: Project Overview Open

Hiroshi Imai, Yuhki Hamae, Kei Amada, Keisuke Nakashima, Ka-Yiu Shum , et al. · 2023

This paper describes the overview of the FLASHING (Finest Legacy Acquisitions of SiO-/ H$_2$O-maser Ignitions by the Nobeyama Generation) project promoted using the 45 m telescope of Nobeyama Radio Observatory, which aims to intensively mo…

Differentiating brain metastasis from glioblastoma by time-dependent diffusion MRI Open

Kiyohisa Kamimura, Yoshiki Kamimura, Tsubasa Nakano, Tomohito Hasegawa, Masanori Nakajo , et al. · 2023

Evolution of the Outflow in the Water Fountain Source IRAS 18043–2116* Open

Lucero Uscanga, Hiroshi Imai, José F. Gómez, Daniel Tafoya, Gábor Orosz , et al. · 2023

We present the spectral and spatial evolution of H 2 O masers associated with the water fountain source IRAS 18043−2116, found in observations with the Nobeyama 45 m Telescope and the Australia Telescope Compact Array. We have found new hi…

A STUDY OF CHANGES AND EVALUATION OF LIVING ENVIRONMENT IN HOUSING RECONSTRUCTIONS IN MOUNTAINOUS AREAS AFTER THE NEPAL EARTHQUAKE Open

Kiyo KOMURAI, Hiroshi Imai, Hiroshi NAKAZAWA, Hiroki Suzuki · 2023

We conducted surveys of sixteen families in Sindhupalchok District, Nepal, who suffered under many damages after the earthquake in 2015, to explore the approaches of disaster recovery of victims in mountainous regions. 1) We collected info…

Quantum-Relaxation Based Optimization Algorithms: Theoretical Extensions Open

Kosei Teramoto, Rudy Raymond, Eyuri Wakakuwa, Hiroshi Imai · 2023

Quantum Random Access Optimizer (QRAO) is a quantum-relaxation based optimization algorithm proposed by Fuller et al. that utilizes Quantum Random Access Code (QRAC) to encode multiple variables of binary optimization in a single qubit. Th…

HINOTORI and Its Perspectives in the Black-Hole Jet Study Open

Toshihisa Tsutsumi, Kotaro Niinuma, Hiroshi Imai, Ryoko Amari, Yusuke Shimizu , et al. · 2023

Simultaneous multi-band very long baseline interferometry (VLBI) observations at millimeter wavelengths have huge potential for various science cases. However, there exist difficulties in expanding the scientific targets, as the sensitivit…

Breath-hold High-resolution T1-weighted Gradient Echo Liver MR Imaging with Compressed Sensing Obtained during the Gadoxetic Acid-enhanced Hepatobiliary Phase: Image Quality and Lesion Visibility Compared with a Standard T1-weighted Sequence Open

Kenichiro Ihara, Hideko Onoda, Masahiro Tanabe, Etsushi Iida, Takaaki Ueda , et al. · 2023

BH HR HBP imaging with CS provided an improved overall image quality, lesion conspicuity, and CE-MRC visualization when compared with standard HBP imaging without extending the acquisition time.

The Role of Entanglement in Quantum-Relaxation Based Optimization Algorithms Open

Kosei Teramoto, Rudy Raymond, Hiroshi Imai · 2023

Quantum Random Access Optimizer (QRAO) is a quantum-relaxation based optimization algorithm proposed by Fuller et al. that utilizes Quantum Random Access Code (QRAC) to encode multiple variables of binary optimization in a single qubit. Di…

Impact of Extracorporeal Membrane Oxygenation in an Infant Treated with Vancomycin: A Case Report Open

Chihiro Shiraishi, Hideo Kato, Hiroshi Imai, Takuya Iwamoto · 2023

Vancomycin is a glycopeptide antibiotic used for prophylaxis and treatment of infections caused by methicillin-resistant Staphylococcus aureus. Although major organ sizes and functions mature during infancy, pharmacokinetic studies, especi…

Development for Japan L-band VLBI Observation Open

Kohei Kurahara, Takuya Akahori, Kazuhiro Hada, Tomoya Hirota, Sota Ikebe , et al. · 2023

Dynamics of the Spontaneous Nucleation of Microtubules Open

Hiroshi Imai, E. Muto · 2023

GTPチューブリンからどのようにして微小管の重合が始まるのか?これまで「自発的核生成」のしくみはほとんど知られていなかったが,筆者らは,溶液中の多様なチューブリンオリゴマー中,形とサイズの両方で一定の基準を満たす,ごく少数のオリゴマーのみが,微小管にまで成長できることを明らかにした.

Overview of the Observing System and Initial Scientific Accomplishments of the East Asian VLBI Network (EAVN) Open

Kazunori Akiyama, Juan Carlos Algaba, Tao An, Keiichi Asada, K. Asanok , et al. · 2022

The East Asian VLBI Network (EAVN) is an international VLBI facility in East Asia and is operated under mutual collaboration between East Asian countries, as well as part of Southeast Asian and European countries. EAVN currently consists o…

A sensitive search for SiO maser emission in planetary nebulae Open

José F. Gómez, Roldán A. Cala, L. F. Miranda, Hiroshi Imai, Mayra Osorio , et al. · 2022

Eight planetary nebulae (PNe) are known to emit OH and/or H 2 O masers, but there is no report of an SiO maser in this type of objects. We present a search for SiO masers in 16 confirmed and candidate PNe, carried out with the Australia Te…

Discovery of SiO masers in the “Water Fountain” source, IRAS 16552–3050 Open

Kei Amada, Hiroshi Imai, Yuhki Hamae, Keisuke Nakashima, Ka-Yiu Shum , et al. · 2022

We report new detections of SiO ν = 1 and ν = 2 J = 1 → 0 masers in the “water fountain” source IRAS 16552-3050, which was observed with the Nobeyama 45 m telescope from March 2021 to April 2023. Water fountains are evolved stars whose H 2…

The Astrometric Animation of Water Masers toward the Mira Variable BX Cam Open

Shuangjing Xu, Hiroshi Imai, Youngjoo Yun, Bo Zhang, María Rioja , et al. · 2022

We report very long baseline interferometry (VLBI) monitoring observations of the 22 GHz water (H 2 O) masers around the Mira variable BX Cam, which were carried out as a part of the EAVN Synthesis of Stellar Maser Animations project. Data…

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