187,575 results on '"A Tamura"'
Search Results
2. The JCMT BISTRO Survey: The Magnetic Fields of the IC 348 Star-forming Region
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Choi, Youngwoo, Kwon, Woojin, Pattle, Kate, Arzoumanian, Doris, Bourke, Tyler L., Hoang, Thiem, Hwang, Jihye, Koch, Patrick M., Sadavoy, Sarah, Bastien, Pierre, Furuya, Ray, Lai, Shih-Ping, Qiu, Keping, Ward-Thompson, Derek, Berry, David, Byun, Do-Young, Chen, Huei-Ru Vivien, Chen, Wen Ping, Chen, Mike, Chen, Zhiwei, Ching, Tao-Chung, Cho, Jungyeon, Choi, Minho, Choi, Yunhee, Coudé, Simon, Chrysostomou, Antonio, Chung, Eun Jung, Dai, Sophia, Debattista, Victor, Di Francesco, James, Diep, Pham Ngoc, Doi, Yasuo, Duan, Hao-Yuan, Duan, Yan, Eswaraiah, Chakali, Fanciullo, Lapo, Fiege, Jason, Fissel, Laura M., Franzmann, Erica, Friberg, Per, Friesen, Rachel, Fuller, Gary, Gledhill, Tim, Graves, Sarah, Greaves, Jane, Griffin, Matt, Gu, Qilao, Han, Ilseung, Hasegawa, Tetsuo, Houde, Martin, Hull, Charles L. H., Inoue, Tsuyoshi, Inutsuka, Shu-ichiro, Iwasaki, Kazunari, Jeong, Il-Gyo, Johnstone, Doug, Karoly, Janik, Könyves, Vera, Kang, Ji-hyun, Lacaille, Kevin, Law, Chi-Yan, Lee, Chang Won, Lee, Hyeseung, Lee, Chin-Fei, Lee, Jeong-Eun, Lee, Sang-Sung, Li, Dalei, Li, Di, Li, Guangxing, Li, Hua-bai, Lin, Sheng-Jun, Liu, Hong-Li, Liu, Tie, Liu, Sheng-Yuan, Liu, Junhao, Longmore, Steven, Lu, Xing, Lyo, A-Ran, Mairs, Steve, Matsumura, Masafumi, Matthews, Brenda, Moriarty-Schieven, Gerald, Nagata, Tetsuya, Nakamura, Fumitaka, Nakanishi, Hiroyuki, Ngoc, Nguyen Bich, Ohashi, Nagayoshi, Onaka, Takashi, Park, Geumsook, Parsons, Harriet, Peretto, Nicolas, Priestley, Felix, Pyo, Tae-Soo, Qian, Lei, Rao, Ramprasad, Rawlings, Jonathan, Rawlings, Mark, Retter, Brendan, Richer, John, Rigby, Andrew, Saito, Hiro, Savini, Giorgio, Seta, Masumichi, Sharma, Ekta, Shimajiri, Yoshito, Shinnaga, Hiroko, Soam, Archana, Kang, Miju, Kataoka, Akimasa, Kawabata, Koji, Kemper, Francisca, Kim, Jongsoo, Kim, Shinyoung, Kim, Gwanjeong, Kim, Kyoung Hee, Kim, Mi-Ryang, Kim, Kee-Tae, Kim, Hyosung, Kirchschlager, Florian, Kirk, Jason, Kobayashi, Masato I. N., Kusune, Takayoshi, Kwon, Jungmi, Tamura, Motohide, Tang, Ya-Wen, Tang, Xindi, Tomisaka, Kohji, Tsukamoto, Yusuke, Viti, Serena, Wang, Hongchi, Wang, Jia-Wei, Wu, Jintai, Xie, Jinjin, Yang, Meng-Zhe, Yen, Hsi-Wei, Yoo, Hyunju, Yuan, Jinghua, Yun, Hyeong-Sik, Zenko, Tetsuya, Zhang, Guoyin, Zhang, Yapeng, Zhang, Chuan-Peng, Zhou, Jianjun, Zhu, Lei, de Looze, Ilse, André, Philippe, Dowell, C. Darren, Eden, David, Eyres, Stewart, Falle, Sam, Gouellec, Valentin J. M. Le, Poidevin, Frédérick, and van Loo, Sven
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Astrophysics - Astrophysics of Galaxies - Abstract
We present 850 $\mu$m polarization observations of the IC 348 star-forming region in the Perseus molecular cloud as part of the B-fields In STar-forming Region Observation (BISTRO) survey. We study the magnetic properties of two cores (HH 211 MMS and IC 348 MMS) and a filamentary structure of IC 348. We find that the overall field tends to be more perpendicular than parallel to the filamentary structure of the region. The polarization fraction decreases with intensity, and we estimate the trend by power-law and the mean of the Rice distribution fittings. The power indices for the cores are much smaller than 1, indicative of possible grain growth to micron size in the cores. We also measure the magnetic field strengths of the two cores and the filamentary area separately by applying the Davis-Chandrasekhar-Fermi method and its alternative version for compressed medium. The estimated mass-to-flux ratios are 0.45-2.20 and 0.63-2.76 for HH 211 MMS and IC 348 MMS, respectively, while the ratios for the filament is 0.33-1.50. This result may suggest that the transition from subcritical to supercritical conditions occurs at the core scale ($\sim$ 0.05 pc) in the region. In addition, we study the energy balance of the cores and find that the relative strength of turbulence to the magnetic field tends to be stronger for IC 348 MMS than HH 211 MMS. The result could potentially explain the different configurations inside the two cores: a single protostellar system in HH 211 MMS and multiple protostars in IC 348 MMS., Comment: Accepted for publication in ApJ. 21 pages, 12 figures
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- 2024
3. ADF22-WEB: A giant barred spiral starburst galaxy in the z = 3.1 SSA22 protocluster core
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Umehata, H., Steidel, C. C., Smail, I., Swinbank, A. M., Monson, E. B., Rosario, D., Lehmer, B. D., Nakanishi, K., Kubo, M., Iono, D., Alexander, D. M., Kohno, K., Tamura, Y., Ivison, R. J., Saito, T., Mitsuhashi, I., Huang, S., and Matsuda, Y.
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Astrophysics - Astrophysics of Galaxies ,Astrophysics - Cosmology and Nongalactic Astrophysics - Abstract
In the present-day universe, the most massive galaxies are ellipticals located in the cores of galaxy clusters, harboring the heaviest super-massive black holes (SMBHs). However the mechanisms that drive the early growth phase and subsequent transformation of these morphology and kinematics of galaxies remain elusive. Here we report (sub)kiloparsec scale observations of stars, gas, and dust in ADF22.A1, a bright dusty starburst galaxy at z=3.1, hosting a heavily obscured active galactic nucleus and residing in a proto-cluster core. ADF22.A1 is a giant spiral galaxy with the kinematics of a rotating disk with rotation velocity Vrot=530+/-10km/s and diameter larger than 30 kpc. The high specific stellar angular momentum of this system, j*=3400+/-600 kpc km/s, requires a mechanism to effectively spin-up ADF22.A1, indicating the importance of accretion from the cosmic web to supply both gas and angular momentum to galaxies in their early gas-rich starburst phase. In its inner region, gas flows along dust lanes in a bar connected with the bright dusty core and the estimated mass ratio of a bulge to SMBH matches the local relation, suggesting that bars are a key mechanism to shape the early co-evolution of these components. Comparison with cosmological simulations shows that ADF22.A1 will likely evolve into a massive elliptical at the present day, experiencing a significant reduction in angular momentum associated with subsequent galaxy mergers., Comment: 13 pages, 12 figures. Submitted
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- 2024
4. Weighing Single-lined Spectroscopic Binaries Using Tidal Effects on Radial Velocities: The Case of V723 Monocerotis
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Tomoyoshi, Mio, Masuda, Kento, Hirano, Teruyuki, Kasagi, Yui, Kawahara, Hajime, Kotani, Takayuki, Kudo, Tomoyuki, Tamura, Motohide, and Vievard, Sébastien
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Astrophysics - Solar and Stellar Astrophysics ,Astrophysics - Earth and Planetary Astrophysics - Abstract
In single-lined spectroscopic binaries (SB1s) where flux variations due to tidal deformation of the primary star (ellipsoidal variations, EVs) are detected, the binary mass can be determined by combining EVs with the primary's radial velocity (RV) variations from orbital motion and information about the primary's radius. This method has been used for mass estimation in close binaries including X-ray systems, but it has been pointed out that contaminating light from sources other than the primary star could introduce systematic errors in the mass and inclination estimates. Here, we focus on the apparent RV variations caused by asymmetric distortion of the absorption lines of the tidally deformed primary star (tidal RV). Because this signal contains information equivalent to that from photometric EVs, it enables mass estimation of the binary system using only the primary star's absorption lines from high-resolution spectroscopic data, providing a potentially more robust approach against contaminating light. We apply the method to the binary system V723 Monocerotis, where both photometric EV and tidal RV signals are detected, and successfully determine the component masses using only the primary star's RVs and projected rotational velocity, without relying on absolute flux measurements or on stellar evolutionary models. The masses derived from the tidal RV model show a reasonable agreement with those obtained from EVs after carefully modeling the flux contamination from the secondary. This result demonstrates that tidal RVs provide a useful alternative means for mass estimation in SB1s., Comment: 13 pages, 3 figures, accepted for publication in ApJ
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- 2024
5. A Novel high-z submm Galaxy Efficient Line Survey in ALMA bands 3 through 8 -- An ANGELS Pilot
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Bakx, T. J. L. C., Amvrosiadis, A., Bendo, G. J., Algera, H. S. B., Serjeant, S., Bonavera, L., Borsato, E., Chen, X., Cox, P., González-Nuevo, J., Hagimoto, M., Harrington, K. C., Ivison, R. J., Kamieneski, P., Marchetti, L., Riechers, D. A., Tsukui, T., van der Werf, P. P., Yang, C., Zavala, J. A., Andreani, P., Berta, S., Cooray, A. R., De Zotti, G., Eales, S., Ikeda, R., Knudsen, K. K., Mitsuhashi, I., Negrello, M., Neri, R., Omont, A., Scott, D., Tamura, Y., Temi, P., and Urquhart, S. A.
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Astrophysics - Astrophysics of Galaxies - Abstract
We use the Atacama Large sub/Millimetre Array (ALMA) to efficiently observe spectral lines across Bands 3, 4, 5, 6, 7, and 8 at high-resolution (0.5" - 0.1") for 16 bright southern Herschel sources at $1.5 < z < 4.2$. With only six and a half hours of observations, we reveal 66 spectral lines in 17 galaxies. These observations detect emission from CO (3-2) to CO(18-17), as well as atomic ([CI](1-0), (2-1), [OI] 145 $\mu$m and [NII] 205 $\mu$m) lines. Additional molecular lines are seen in emission (${\rm H_2O}$ and ${\rm H_2O^+}$) and absorption (OH$^+$ and CH$^+$). The morphologies based on dust continuum ranges from extended sources to strong lensed galaxies with magnifications between 2 and 30. CO line transitions indicate a diverse set of excitation conditions with a fraction of the sources ($\sim 35$%) showcasing dense, warm gas. The resolved gas to star-formation surface densities vary strongly per source, and suggest that the observed diversity of dusty star-forming galaxies could be a combination of lensed, compact dusty starbursts and extended, potentially-merging galaxies. The predicted gas depletion timescales are consistent with 100 Myr to 1 Gyr, but require efficient fueling from the extended gas reservoirs onto the more central starbursts, in line with the Doppler-shifted absorption lines that indicate inflowing gas for two out of six sources. This pilot paper explores a successful new method of observing spectral lines in large samples of galaxies, supports future studies of larger samples, and finds that the efficiency of this new observational method will be further improved with the planned ALMA Wideband Sensitivity Upgrade., Comment: Accepted for publication in MNRAS. 42 pages, including 20 figures + spectra. Comments and discussion are warmly welcomed
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- 2024
6. Large Interferometer For Exoplanets (LIFE). XIV. Finding terrestrial protoplanets in the galactic neighborhood
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Cesario, Lorenzo, Lichtenberg, Tim, Alei, Eleonora, Carrión-González, Óscar, Dannert, Felix A., Defrère, Denis, Ertel, Steve, Fortier, Andrea, Muñoz, A. García, Glauser, Adrian M., Hansen, Jonah T., Helled, Ravit, Huber, Philipp A., Ireland, Michael J., Kammerer, Jens, Laugier, Romain, Lillo-Box, Jorge, Menti, Franziska, Meyer, Michael R., Noack, Lena, Quanz, Sascha P., Quirrenbach, Andreas, Rugheimer, Sarah, van der Tak, Floris, Wang, Haiyang S., Anger, Marius, Balsalobre-Ruza, Olga, Bhattarai, Surendra, Braam, Marrick, Castro-González, Amadeo, Cockell, Charles S., Constantinou, Tereza, Cugno, Gabriele, Davoult, Jeanne, Güdel, Manuel, Hernitschek, Nina, Hinkley, Sasha, Itoh, Satoshi, Janson, Markus, Johansen, Anders, Jones, Hugh R. A., Kane, Stephen R., van Kempen, Tim A., Kislyakova, Kristina G., Korth, Judith, Kovacevic, Andjelka B., Kraus, Stefan, Kuiper, Rolf, Mathew, Joice, Matsuo, Taro, Miguel, Yamila, Min, Michiel, Navarro, Ramon, Ramirez, Ramses M., Rauer, Heike, Ricketti, Berke Vow, Romagnolo, Amedeo, Schlecker, Martin, Sneed, Evan L., Squicciarini, Vito, Stassun, Keivan G., Tamura, Motohide, Viudez-Moreiras, Daniel, Wordsworth, Robin D., and Collaboration, the LIFE
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Astrophysics - Earth and Planetary Astrophysics ,Astrophysics - Instrumentation and Methods for Astrophysics ,Physics - Geophysics - Abstract
The increased brightness temperature of young rocky protoplanets during their magma ocean epoch makes them potentially amenable to atmospheric characterization to distances from the solar system far greater than thermally equilibrated terrestrial exoplanets, offering observational opportunities for unique insights into the origin of secondary atmospheres and the near surface conditions of prebiotic environments. The Large Interferometer For Exoplanets (LIFE) mission will employ a space-based mid-infrared nulling interferometer to directly measure the thermal emission of terrestrial exoplanets. Here, we seek to assess the capabilities of various instrumental design choices of the LIFE mission concept for the detection of cooling protoplanets with transient high-temperature magma ocean atmospheres, in young stellar associations in particular. Using the LIFE mission instrument simulator (LIFEsim) we assess how specific instrumental parameters and design choices, such as wavelength coverage, aperture diameter, and photon throughput, facilitate or disadvantage the detection of protoplanets. We focus on the observational sensitivities of distance to the observed planetary system, protoplanet brightness temperature using a blackbody assumption, and orbital distance of the potential protoplanets around both G- and M-dwarf stars. Our simulations suggest that LIFE will be able to detect (S/N $\geq$ 7) hot protoplanets in young stellar associations up to distances of $\approx$100 pc from the solar system for reasonable integration times (up to $\sim$hours). Detection of an Earth-sized protoplanet orbiting a solar-sized host star at 1 AU requires less than 30 minutes of integration time. M-dwarfs generally need shorter integration times. The contribution from wavelength regions $<$6 $\mu$m is important for decreasing the detection threshold and discriminating emission temperatures., Comment: 18 pages, 19 figures; accepted for publication in A&A
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- 2024
7. SCExAO/CHARIS Near-Infrared Scattered-Light Imaging and Integral Field Spectropolarimetry of the AB Aurigae Protoplanetary System
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Dykes, Erica, Currie, Thayne, Lawson, Kellen, Lucas, Miles, Kudo, Tomoyuki, Chen, Minghan, Guyon, Olivier, Groff, Tyler D, Lozi, Julien, Chilcote, Jeffrey, Brandt, Timothy D., Vievard, Sebastien, Skaf, Nour, Deo, Vincent, Morsy, Mona El, Bovie, Danielle, Uyama, Taichi, Grady, Carol, Sitko, Michael, Hashimoto, Jun, Martinache, Frantz, Jovanovic, Nemanja, Tamura, Motohide, and Kasdin, N. Jeremy
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Astrophysics - Earth and Planetary Astrophysics ,Astrophysics - Instrumentation and Methods for Astrophysics ,Astrophysics - Solar and Stellar Astrophysics - Abstract
We analyze near-infrared integral field spectropolarimetry of the AB Aurigae protoplanetary disk and protoplanet (AB Aur b), obtained with SCExAO/CHARIS in 22 wavelength channels covering the J, H, and K passbands ($\lambda_{\rm o}$ = 1.1--2.4 $\mu m$) over angular separations of $\rho$ $\approx$ 0.13" to 1.1" ($\sim$20--175 au). Our images resolve spiral structures in the disk in each CHARIS channel. At the longest wavelengths, the data may reveal an extension of the western spiral seen in previous polarimetric data at $\rho$ $<$ 0.3" out to larger distances clockwise from the protoplanet AB Aur b, coincident with the ALMA-detected $CO$ gas spiral. While AB Aur b is detectable in complementary total intensity data, it is a non-detection in polarized light at $\lambda$ $>$ 1.3 $\mu $m. While the observed disk color is extremely red across $JHK$, the disk has a blue intrinsic scattering color consistent with small dust grains. The disk's polarization spectrum is redder than AB Aur b's total intensity spectrum. The polarization fraction peaks at $\sim$ 0.6 along the major disk axis. Radiative transfer modeling of the CHARIS data shows that small, porous dust grains with a porosity of $p$ = 0.6--0.8 better reproduce the scattered-light appearance of the disk than more compact spheres ($p$ = 0.3), especially the polarization fraction. This work demonstrates the utility of integral field spectropolarimetry to characterize structures in protoplanetary disks and elucidate the properties of the disks' dust., Comment: 23 pages, 17 Figures, accepted to AAS Journals
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- 2024
8. Atmospheric retrieval of Subaru/IRD high-resolution spectrum of the archetype T-type brown dwarf Gl 229 B
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Kawashima, Yui, Kawahara, Hajime, Kasagi, Yui, Ishikawa, Hiroyuki Tako, Masuda, Kento, Kotani, Takayuki, Kudo, Tamoyuki, Hirano, Teruyuki, Kuzuhara, Masayuki, Nugroho, Stevanus K, Livingston, John, Harakawa, Hiroki, Nishikawa, Jun, Omiya, Masashi, Takarada, Takuya, Tamura, Motohide, and Ueda, Akitoshi
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Astrophysics - Earth and Planetary Astrophysics ,Astrophysics - Solar and Stellar Astrophysics - Abstract
Brown dwarfs provide a unique opportunity to study atmospheres and their physical and chemical processes with high precision, especially in temperature ranges relevant to exoplanets. In this study, we performed high-resolution ($R \sim 70,000$) spectroscopy using Subaru/IRD of Gl 229 B, the first discovered T-type (T7.0p) brown dwarf, which orbits an M1V host star at a separation of 33 au. We conducted atmospheric retrieval on the reduced $H$-band spectrum using the high-resolution spectrum model compatible with automatic differentiation and GPU, ExoJAX. In contrast to previous retrieval studies on medium-resolution spectra, we obtained a C/O ratio consistent with that of the host star, aligning with the expected formation process for such a massive brown dwarf. Additionally, based on the strong constraint on temperature from the high-resolution spectrum and previously measured photometric magnitude, our analysis indicates that Gl 229 B is a binary, which was also proposed by Brandt et al. (2021). Finally, we validated current molecular line lists by leveraging the obtained high-precision, high-resolution spectrum of this warm ($\sim 900$ K) atmosphere. This study highlights the importance of observing companion brown dwarfs as benchmark objects for establishing characterization techniques for low-mass objects and enhancing our understanding of their atmospheres, given the wealth of available information and the relative ease of observation., Comment: 16 pages, 9 figures, submitted to AAS
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- 2024
9. JWST/NIRSpec spectroscopy of intermediate-mass quiescent galaxies at $z \sim 3-4$
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Sato, Riku A., Inoue, Akio K., Harikane, Yuichi, Shimakawa, Rhythm, Sugahara, Yuma, Tamura, Yoichi, Hashimoto, Takuya, Ito, Kei, Yamanaka, Satoshi, Mawatari, Ken, Fudamoto, Yoshinobu, and Ren, Yi W.
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Astrophysics - Astrophysics of Galaxies - Abstract
We present the analysis of three intermediate-mass quiescent galaxies (QGs) with stellar masses of $\sim10^{10}M_{\rm \odot}$ at redshifts $z\sim 3 - 4$ using NIRSpec low-resolution spectroscopy. Utilising the SED fitting code BAGPIPES, we confirm these target galaxies are consistent with quiescent population, with their specific star formation rates (sSFR) falling below 2-dex the star-forming main sequence at the same redshifts. Additionally, we identify these QGs to be less massive than those discovered in previous works, particularly prior to the JWST era. Two of our target galaxies exhibit the potentially-blended H${\alpha}$+[NII] emission line within their spectra with $S/N>5$. We discuss whether this feature comes from an Active Galactic Nucleus (AGN) or star formation although future high-resolution spectroscopy is required to reach a conclusion. One of the target galaxies is covered by JWST/NIRCam imaging of the PRIMER survey. Using the 2D profile fitting code Galfit, we examine its morphology, revealing a disc-like profile with a S\'{e}rsic index of $n=1.1 \pm 0.1$. On the size-mass relation, we find a potential distinction between less-massive ($\log_{10}{(M_*/M_\odot)}<10.3$) and massive ($\log_{10}{(M_*/M_\odot)}>10.3$) QGs in their evolutionary pathways. The derived quenching timescales for our targets are less than 1 Gyr. This may result from these galaxies being quenched by AGN feedback, supporting the AGN scenario of the emission line features., Comment: MNRAS accepted
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- 2024
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10. Meissner effect in non-Hermitian superconductors
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Tamura, Shun, Müller, Helene, and Kornich, Viktoriia
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Condensed Matter - Superconductivity ,Condensed Matter - Mesoscale and Nanoscale Physics - Abstract
We study theoretically Meissner effect in non-Hermitian systems of BCS type via superfluid stiffness. We show that depending on the values of the mean fields, chemical potential, and temperature, we obtain paramagnetic or diamagnetic Meissner effect. Notably, positive real part of the product of mean fields guarantees diamagnetic Meissner effect in an $s$-wave 3D non-Hermitian superconductor. Once the mean fields are close to being anti-Hermitian, 2D $s$-, $p_x$-, and $d$-wave superconductors exhibit interesting behaviour, including paramagnetic Meissner effect for certain parameters.
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- 2024
11. Use of Real-World Data and Real-World Evidence in Rare Disease Drug Development: A Statistical Perspective
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Chen, Jie, Gruber, Susan, Lee, Hana, Chu, Haitao, Lee, Shiowjen, Tian, Haijun, Wang, Yan, He, Weili, Jemielita, Thomas, Song, Yang, Tamura, Roy, Tian, Lu, Zhao, Yihua, Chen, Yong, van der Laan, Mark, and Nie, Lei
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Statistics - Applications - Abstract
Real-world data (RWD) and real-world evidence (RWE) have been increasingly used in medical product development and regulatory decision-making, especially for rare diseases. After outlining the challenges and possible strategies to address the challenges in rare disease drug development (see the accompanying paper), the Real-World Evidence (RWE) Scientific Working Group of the American Statistical Association Biopharmaceutical Section reviews the roles of RWD and RWE in clinical trials for drugs treating rare diseases. This paper summarizes relevant guidance documents and frameworks by selected regulatory agencies and the current practice on the use of RWD and RWE in natural history studies and the design, conduct, and analysis of rare disease clinical trials. A targeted learning roadmap for rare disease trials is described, followed by case studies on the use of RWD and RWE to support a natural history study and marketing applications in various settings.
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- 2024
12. Challenges and Possible Strategies to Address Them in Rare Disease Drug Development: A Statistical Perspective
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Chen, Jie, Nie, Lei, Lee, Shiowjen, Chu, Haitao, Tian, Haijun, Wang, Yan, He, Weili, Jemielita, Thomas, Gruber, Susan, Song, Yang, Tamura, Roy, Tian, Lu, Zhao, Yihua, Chen, Yong, van der Laan, Mark, and Lee, Hana
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Statistics - Applications - Abstract
Developing drugs for rare diseases presents unique challenges from a statistical perspective. These challenges may include slowly progressive diseases with unmet medical needs, poorly understood natural history, small population size, diversified phenotypes and geneotypes within a disorder, and lack of appropriate surrogate endpoints to measure clinical benefits. The Real-World Evidence (RWE) Scientific Working Group of the American Statistical Association Biopharmaceutical Section has assembled a research team to assess the landscape including challenges and possible strategies to address these challenges and the role of real-world data (RWD) and RWE in rare disease drug development. This paper first reviews the current regulations by regulatory agencies worldwide and then discusses in more details the challenges from a statistical perspective in the design, conduct, and analysis of rare disease clinical trials. After outlining an overall development pathway for rare disease drugs, corresponding strategies to address the aforementioned challenges are presented. Other considerations are also discussed for generating relevant evidence for regulatory decision-making on drugs for rare diseases. The accompanying paper discusses how RWD and RWE can be used to improve the efficiency of rare disease drug development.
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- 2024
13. Differentiable Modeling of Planet and Substellar Atmosphere: High-Resolution Emission, Transmission, and Reflection Spectroscopy with ExoJAX2
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Kawahara, Hajime, Kawashima, Yui, Tada, Shotaro, Ishikawa, Hiroyuki Tako, Hosokawa, Ko, Kasagi, Yui, Kotani, Takayuki, Masuda, Kento, Nuguroho, Stevanus, Tamura, Motohide, Yama, Hibiki, Kitzmann, Daniel, Minesi, Nicolas, and Morris, Brett M.
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Astrophysics - Earth and Planetary Astrophysics ,Astrophysics - Instrumentation and Methods for Astrophysics ,Astrophysics - Solar and Stellar Astrophysics - Abstract
Modeling based on differentiable programming holds great promise for astronomy, as it can employ techniques such as Hamiltonian Monte Carlo, gradient-based optimization, and other machine learning techniques. This new programming paradigm has motivated us to develop the first auto-differentiable spectrum model of exoplanets and brown dwarfs, ExoJAX (Kawahara et al. 2022). ExoJAX is designed to directly calculate cross-sections as functions of temperature and pressure, rather than interpolating tabulated data, to minimize errors in high-dispersion spectra modeling. However, its application was primarily proof-of-concept and limited to narrowband high-dispersion emission spectroscopy. In this paper, we have enhanced the differentiable opacity calculation using a new fast and memory-efficient algorithm, and have developed differentiable radiative transfer schemes, including emission, transmission, and reflection spectroscopy. These enhancements significantly expand the range of applications, as demonstrated through actual atmospheric retrievals: high-dispersion emission spectra of the brown dwarf GL229 B, medium-dispersion transmission spectra of the hot Saturn WASP-39 b from JWST, and high-dispersion reflection spectra of Jupiter. We obtained a C/O ratio for GL229 B consistent with its host star, constrained WASP-39 b's radial velocity from molecular fine structures at original resolution ($R \sim 3,000$), and estimated Jupiter's metallicity consistent with previous studies., Comment: 32 pages, 12 figures, submitted. ExoJAX is available at https://github.com/HajimeKawahara/exojax. ExoJAX2 is scheduled to be released after the review process
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- 2024
14. Robotic Backchanneling in Online Conversation Facilitation: A Cross-Generational Study
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Kobuki, Sota, Seaborn, Katie, Tokunaga, Seiki, Fukumori, Kosuke, Hidaka, Shun, Tamura, Kazuhiro, Inoue, Koji, Kawahara, Tatsuya, and Otake-Mastuura, Mihoko
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Computer Science - Robotics ,Computer Science - Computation and Language ,Computer Science - Human-Computer Interaction - Abstract
Japan faces many challenges related to its aging society, including increasing rates of cognitive decline in the population and a shortage of caregivers. Efforts have begun to explore solutions using artificial intelligence (AI), especially socially embodied intelligent agents and robots that can communicate with people. Yet, there has been little research on the compatibility of these agents with older adults in various everyday situations. To this end, we conducted a user study to evaluate a robot that functions as a facilitator for a group conversation protocol designed to prevent cognitive decline. We modified the robot to use backchannelling, a natural human way of speaking, to increase receptiveness of the robot and enjoyment of the group conversation experience. We conducted a cross-generational study with young adults and older adults. Qualitative analyses indicated that younger adults perceived the backchannelling version of the robot as kinder, more trustworthy, and more acceptable than the non-backchannelling robot. Finally, we found that the robot's backchannelling elicited nonverbal backchanneling in older participants., Comment: Published at Proceedings of the 2023 32nd IEEE International Conference on Robot and Human Interactive Communication (RO-MAN 2023)
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- 2024
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15. Tidally Heated Sub-Neptunes, Refined Planetary Compositions, and Confirmation of a Third Planet in the TOI-1266 System
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Greklek-McKeon, Michael, Vissapragada, Shreyas, Knutson, Heather A., Fukui, Akihiko, Saidel, Morgan, Barrientos, Jonathan Gomez, Levine, W. Garrett, Behmard, Aida, Batygin, Konstantin, Chachan, Yayaati, Vasisht, Gautam, Hu, Renyu, Cloutier, Ryan, Latham, David, López-Morales, Mercedes, Vanderburg, Andrew, Heffner, Carolyn, Nied, Paul, Milburn, Jennifer, Wilson, Isaac, Roderick, Diana, Koviak, Kathleen, Barlow, Tom, Stone, John F., Kiman, Rocio, Korth, Judith, de Leon, Jerome P., Fukuda, Izuru, Hayashi, Yuya, Ikoma, Masahiro, Ikuta, Kai, Isogai, Keisuke, Kawai, Yugo, Kawauchi, Kiyoe, Kusakabe, Nobuhiko, Livingston, John H., Mori, Mayuko, Narita, Norio, Tamura, Motohide, Watanabe, Noriharu, and Fernández-Rodríguez, Gareb
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Astrophysics - Earth and Planetary Astrophysics - Abstract
TOI-1266 is a benchmark system of two temperate ($<$ 450 K) sub-Neptune-sized planets orbiting a nearby M dwarf exhibiting a rare inverted architecture with a larger interior planet. In this study, we characterize transit timing variations (TTVs) in the TOI-1266 system using high-precision ground-based follow-up and new TESS data. We confirm the presence of a third exterior non-transiting planet, TOI-1266 d (P = 32.5 d, $M_d$ = 3.68$^{+1.05}_{-1.11} M_{\oplus}$), and combine the TTVs with archival radial velocity (RV) measurements to improve our knowledge of the planetary masses and radii. We find that, consistent with previous studies, TOI-1266 b ($R_b$ = 2.52 $\pm$ 0.08 $R_{\oplus}$, $M_b$ = 4.46 $\pm$ 0.69 $M_{\oplus}$) has a low bulk density requiring the presence of a hydrogen-rich envelope, while TOI-1266 c ($R_c$ = 1.98 $\pm$ 0.10 $R_{\oplus}$, $M_c$ = 3.17 $\pm$ 0.76 $M_{\oplus}$) has a higher bulk density that can be matched by either a hydrogen-rich or water-rich envelope. Our new dynamical model reveals that this system is arranged in a rare configuration with the inner and outer planets located near the 3:1 period ratio with a non-resonant planet in between them. Our dynamical fits indicate that the inner and outer planet have significantly nonzero eccentricities ($e_b + e_d = 0.076^{+0.029}_{-0.019}$), suggesting that TOI-1266 b may have an inflated envelope due to tidal heating. Finally, we explore the corresponding implications for the formation and long-term evolution of the system, which contains two of the most favorable cool ($<$ 500 K) sub-Neptunes for atmospheric characterization with JWST., Comment: 36 pages, 19 figures, 5 tables, submitted to The Astronomical Journal
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- 2024
16. High-Speed Multifunctional Photonic Memory on a Foundry-Processed Photonic Platform
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Kari, Sadra Rahimi, Tamura, Marcus, Guo, Zhimu, Huang, Yi-Siou, Sun, Hongyi, Lian, Chuanyu, Nobile, Nicholas, Erickson, John, Moridsadat, Maryam, Ocampo, Carlos A. Ríos, Shastri, Bhavin J, and Youngblood, Nathan
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Physics - Optics ,Physics - Applied Physics - Abstract
The integration of computing with memory is essential for distributed, massively parallel, and adaptive architectures such as neural networks in artificial intelligence (AI). Accelerating AI can be achieved through photonic computing, but it requires nonvolatile photonic memory capable of rapid updates during on-chip training sessions or when new information becomes available during deployment. Phase-change materials (PCMs) are promising for providing compact, nonvolatile optical weighting; however, they face limitations in terms of bit precision, programming speed, and cycling endurance. Here, we propose a novel photonic memory cell that merges nonvolatile photonic weighting using PCMs with high-speed, volatile tuning enabled by an integrated PN junction. Our experiments demonstrate that the same PN modulator, fabricated via a foundry compatible process, can achieve dual functionality. It supports coarse programmability for setting initial optical weights and facilitates high-speed fine-tuning to adjust these weights dynamically. The result showcases a 400-fold increase in volatile tuning speed and a 10,000-fold enhancement in efficiency. This multifunctional photonic memory with volatile and nonvolatile capabilities could significantly advance the performance and versatility of photonic memory cells, providing robust solutions for dynamic computing environments.
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- 2024
17. Validation of up to seven TESS planet candidates through multi-colour transit photometry using MuSCAT2 data
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Peláez-Torres, A., Esparza-Borges, E., Pallé, E., Parviainen, H., Murgas, F., Morello, G., Zapatero-Osorio, M. R., Korth, J., Narita, N., Fukui, A., Carleo, I., Luque, R., García, N. Abreu, Barkaoui, K., Boyle, A., Béjar, V. J. S., Calatayud-Borras, Y., Cheryasov, D. V., Christiansen, J. L., Ciardi, D. R., Enoc, G., Essack, Z., Fukuda, I., Furesz, G., Galán, D., Geraldía-González, S., Giacalone, S., Gill, H., Gonzales, E. J., Hayashi, Y., Ikuta, K., Isogai, K., Kagetani, T., Kawai, Y., Kawauchi, K., Klagyvik, P., Kodama, T., Kusakabe, N., Laza-Ramos, A., de Leon, J. P., Livingston, J. H., Lund, M. B., Madrigal-Aguado, A., Meni, P., Mori, M., Torres, S. Muñoz, Orell-Miquel, J., Puig, M., Ricker, G., Sánchez-Benavente, M., Savel, A. B., Schlieder, J. E., Schwarz, R. P., Sefako, R., Sosa-Guillén, P., Stangret, M., Stockdale, C., Tamura, M., Terada, Y., Twicken, J. D., Watanabe, N., Winn, J., Zheltoukhov, S. G., Ziegler, C., and Zou, Y.
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Astrophysics - Earth and Planetary Astrophysics - Abstract
The TESS mission searches for transiting exoplanets by monitoring the brightness of hundreds of thousands of stars across the entire sky. M-type planet hosts are ideal targets for this mission due to their smaller size and cooler temperatures, which makes it easier to detect smaller planets near or within their habitable zones. Additionally, M~dwarfs have a smaller contrast ratio between the planet and the star, making it easier to measure the planet's properties accurately. Here, we report the validation analysis of 13 TESS exoplanet candidates orbiting around M dwarfs. We studied the nature of these candidates through a multi-colour transit photometry transit analysis using several ground-based instruments (MuSCAT2, MuSCAT3, and LCO-SINISTRO), high-spatial resolution observations, and TESS light curves. We present the validation of five new planetary systems: TOI-1883b, TOI-2274b, TOI2768b, TOI-4438b, and TOI-5319b, along with compelling evidence of a planetary nature for TOIs 2781b and 5486b. We also present an empirical definition for the Neptune desert boundaries. The remaining six systems could not be validated due to large true radius values overlapping with the brown dwarf regime or, alternatively, the presence of chromaticity in the MuSCAT2 light curves.
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- 2024
18. Spectroscopy using a visible photonic lantern at the Subaru telescope: Laboratory characterization and first on-sky demonstration on Ikiiki ({\alpha} Leo) and `Aua ({\alpha} Ori)
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Vievard, Sébastien, Lallement, Manon, Leon-Saval, Sergio, Guyon, Olivier, Jovanovic, Nemanja, Huby, Elsa, Lacour, Sylvestre, Lozi, Julien, Deo, Vincent, Ahn, Kyohoon, Lucas, Miles, Sallum, Steph, Norris, Barnaby, Betters, Chris, Amezcua-Correa, Rodrygo, Yerolatsitis, Stephanos, Fitzgerald, Michael, Lin, Jon, Kim, Yoo Jung, Gatkine, Pradip, Kotani, Takayuki, Tamura, Motohide, Currie, Thayne, Kenchington, Harry-Dean, Martin, Guillermo, and Perrin, Guy
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Astrophysics - Instrumentation and Methods for Astrophysics - Abstract
Photonic lanterns are waveguide devices enabling high throughput single mode spectroscopy and high angular resolution. We aim to present the first on-sky demonstration of a photonic lantern (PL) operating in visible light, to measure its throughput and assess its potential for high-resolution spectroscopy of compact objects. We used the SCExAO instrument (a double stage extreme AO system installed at the Subaru telescope) and FIRST mid-resolution spectrograph (R 3000) to test the visible capabilities of the PL on internal source and on-sky observations. The best averaged coupling efficiency over the PL field of view was measured at 51% +/- 10% with a peak at 80%. We also investigate the relationship between coupling efficiency and the Strehl ratio for a PL, comparing them with those of a single-mode fiber (SMF). Findings show that in the AO regime, a PL offers better coupling efficiency performance than a SMF, especially in the presence of low spatial frequency aberrations. We observed Ikiiki (alpha Leo - mR = 1.37) and `Aua (alpha Ori - mR = -1.17) at a frame rate of 200 Hz. Under median seeing conditions (about 1 arcsec measured in H band) and large tip/tilt residuals (over 20 mas), we estimated an average light coupling efficiency of 14.5% +/- 7.4%, with a maximum of 42.8% at 680 nm. We were able to reconstruct both star's spectra, containing various absorption lines. The successful demonstration of this device opens new possibilities in terms of high throughput single-mode fiber-fed spectroscopy in the Visible. The demonstrated on-sky coupling efficiency performance would not have been achievable with a single SMF injection setup under similar conditions, partly because the residual tip/tilt alone exceeded the field of view of a visible SMF (18 mas at 700 nm). Thus emphasizing the enhanced resilience of PL technology to such atmospheric disturbances. The additional, Comment: Accepted in Astronomy and Astrophysics journal on 9/11/2024
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- 2024
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19. Design, scientific goals, and performance of the SCExAO survey for planets around accelerating stars
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Morsy, Mona El, Currie, Thayne, Kuzuhara, Masayuki, Chilcote, Jeffrey, Guyon, Olivier, Tobin, Taylor L., Brandt, Timothy, An, Qier, Anh, Kyohoon, Bovie, Danielle, Deo, Vincent, Groff, Tyler, Gu, Ziying, Janson, Markus, Jovanovic, Nemanja, Li, Yiting, Lawson, Kellen, Lozi, Julien, Lucas, Miles, Marois, Christian, Murakami, Naoshi, Nielsen, Eric, Norris, Barnaby, Skaf, Nour, Tamura, Motohide, Thompson, William, Uyama, Taichi, and Vievard, Sebastien
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Astrophysics - Earth and Planetary Astrophysics ,Astrophysics - Instrumentation and Methods for Astrophysics - Abstract
We describe the motivation, design, and early results for our 42-night, 125 star Subaru/SCExAO direct imaging survey for planets around accelerating stars. Unlike prior large surveys, ours focuses only on stars showing evidence for an astrometric acceleration plausibly due to the dynamical pull of an unseen planet or brown dwarf. Our program is motivated by results from a recent pilot program that found the first planet jointly discovered from direct imaging and astrometry and resulted in a planet and brown dwarf discovery rate substantially higher than previous unbiased surveys like GPIES. The first preliminary results from our program reveal multiple new companions; discovered planets and brown dwarfs can be further characterized with follow-up data, including higher-resolution spectra. Finally, we describe the critical role this program plays in supporting the Roman Space Telescope Coronagraphic Instrument, providing a currently-missing list of targets suitable for the CGI technological demonstration without which the CGI tech demo risks failure., Comment: 13 pages, 7 figures; Proc. SPIE in press
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- 2024
20. Modeling Drivers' Risk Perception via Attention to Improve Driving Assistance
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Biswas, Abhijat, Gideon, John, Tamura, Kimimasa, and Rosman, Guy
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Computer Science - Robotics ,Computer Science - Human-Computer Interaction - Abstract
Advanced Driver Assistance Systems (ADAS) alert drivers during safety-critical scenarios but often provide superfluous alerts due to a lack of consideration for drivers' knowledge or scene awareness. Modeling these aspects together in a data-driven way is challenging due to the scarcity of critical scenario data with in-cabin driver state and world state recorded together. We explore the benefits of driver modeling in the context of Forward Collision Warning (FCW) systems. Working with real-world video dataset of on-road FCW deployments, we collect observers' subjective validity rating of the deployed alerts. We also annotate participants' gaze-to-objects and extract 3D trajectories of the ego vehicle and other vehicles semi-automatically. We generate a risk estimate of the scene and the drivers' perception in a two step process: First, we model the movement of vehicles in a given scenario as a joint trajectory forecasting problem. Then, we reason about the drivers' risk perception of the scene by counterfactually modifying the input to the forecasting model to represent the drivers' actual observations of vehicles in the scene. The difference in these behaviours gives us an estimate of driver behaviour that accounts for their actual (inattentive) observations and their downstream effect on overall scene risk. We compare both a learned scene representation as well as a more traditional ``worse-case'' deceleration model to achieve the future trajectory forecast. Our experiments show that using this risk formulation to generate FCW alerts may lead to improved false positive rate of FCWs and improved FCW timing.
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- 2024
21. Mini-Proceedings of the 'Fourth International Workshop on the Extension Project for the J-PARC Hadron Experimental Facility (HEF-ex 2024)'
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Achenbach, P., Aoki, K., Aoki, S., Curceanu, C., Diehl, S., Doi, T., Endo, M., Fujita, M., Fukuda, T., Garcia-Tecocoatzi, H., Geng, L. S., Gunji, T., Hanhart, C., Harada, M., Harada, T., Hayakawa, S., He, B. R., Hiyama, E., Honda, R., Ichikawa, Y., Isaka, M., Jido, D., Jinno, A., Kamada, K., Kamiya, Y., Kong, Y. K., Liu, Z. W., Lu, J. X., Miwa, K., Mizutani, K., Murakami, K., Muto, R., Murase, K., Nagao, S., Nanamura, T., Nanjo, H., Nara, Y., Ohnishi, A., Qiu, J. W., Sakaguchi, A., Sakuma, F., Santopinto, E., Scordo, A., Sekihara, T., Seong, C., Shevchenko, N. V., Stone, J. R., Strakovsky, I., Suzuki, K., Takahashi, H., Takizawa, M., Tamura, H., Tomida, N., Umeya, A., Doce, O. Vázquez, Yamagata-Sekihara, J., Yamamoto, T. O., Xiao, Y., Yin, Z., Yu, Z., and Zou, B. S.
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Nuclear Experiment ,High Energy Physics - Experiment ,High Energy Physics - Phenomenology ,Nuclear Theory - Abstract
The mini proceedings of the "Fourth International Workshop on the Extension Project for the J-PARC Hadron Experimental Facility (HEF-ex 2024) [https://kds.kek.jp/event/46965]" held at J-PARC, February 19-21, 2024, are presented. The workshop was devoted to discussing the physics case that connects both the present and the future Hadron Experimental Facility at J-PARC, covering a wide range of topics in flavor, hadron, and nuclear physics related to both experimental and theoretical activities being conducted at the facility.
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- 2024
22. MASTER OT J030227.28+191754.5: an unprecedentedly energetic dwarf nova outburst
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Tampo, Yusuke, Kato, Taichi, Isogai, Keisuke, Kimura, Mariko, Kojiguchi, Naoto, Nogami, Daisaku, Ito, Junpei, Shibata, Masaaki, Yamanaka, Masayuki, Taguchi, Kenta, Maehara, Hiroyuki, Itoh, Hiroshi, Matsumoto, Katsura, Nakagawa, Momoka, Nishida, Yukitaka, Dvorak, Shawn, Murata, Katsuhiro L., Hosokawa, Ryohei, Imai, Yuri, Ito, Naohiro, Niwano, Masafumi, Sato, Shota, Noto, Ryotaro, Yamaguchi, Ryodai, Schramm, Malte, Oasa, Yumiko, Kanai, Takahiro, Sasaki, Yu, Tordai, Tamás, Vanmunster, Tonny, Kiyota, Seiichiro, Katysheva, Nataly, Shugarov, Sergey Yu., Zubareva, Alexandra M., Antipin, Sergei, Ikonnikova, Natalia, Belinski, Alexandr, Dubovsky, Pavol A., Medulka, Tomáš, Takahashi, Jun, Takayama, Masaki, Ohshima, Tomohito, Saito, Tomoki, Tozuka, Miyako, Sako, Shigeyuki, Tanaka, Masaomi, Tominaga, Nozomu, Horiuchi, Takashi, Hanayama, Hidekazu, Reichart, Daniel E., Kouprianov, Vladimir V., Davidson Jr, James W., Caton, Daniel B., Romanov, Filipp D., Lane, David J., Hambsch, Franz-josef, Narita, Norio, Fukui, Akihiko, Ikoma, Masahiro, Tamura, Motohide, Kawabata, Koji S., Nakaoka, Tatsuya, and Imazawa, Ryo
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Astrophysics - Solar and Stellar Astrophysics ,Astrophysics - High Energy Astrophysical Phenomena - Abstract
We present a detailed study of the MASTER OT J030227.28+191754.5 outburst in 2021-2022, reaching an amplitude of 10.2 mag and a duration of 60 d. The detections of (1) the double-peaked optical emission lines, and (2) the early and ordinary superhumps, established that MASTER OT J030227.28+191754.5 is an extremely energetic WZ Sge-type dwarf nova (DN). Based on the superhump observations, we obtained its orbital period and mass ratio as 0.05986(1) d and 0.063(1), respectively. These are within a typical range of low-mass-ratio DNe. According to the binary parameters derived based on the thermal-tidal instability model, our analyses showed that (1) the standard disk model requires an accretion rate $\simeq$ 10$^{20}$ g s$^{-1}$ to explain its peak optical luminosity and (2) large mass was stored in the disk at the outburst onset. These cannot be explained solely by the impact of its massive ($\gtrsim$ 1.15 M$_\odot$) primary white dwarf implied by Kimura et al. (2023). Instead, we propose that the probable origin of this enormously energetic DN outburst is the even lower quiescence viscosity than other WZ Sge-type DNe. This discussion is qualitatively valid for most possible binary parameter spaces unless the inclination is low ($\lesssim 40^\circ$) enough for the disk to be bright explaining the outburst amplitude. Such low inclinations, however, would not allow detectable amplitude of early superhumps in the current thermal-tidal instability model. The optical spectra at outburst maximum showed the strong emission lines of Balmer, He I, and He II series whose core is narrower than $\sim 800$ km s$^{-1}$. Considering its binary parameters, a Keplerian disk cannot explain this narrow component, but the presumable origin is disk winds., Comment: 23 pages, 13 figures, 2 tables. Accepted by PASJ. Part of the online supplemental information is included
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- 2024
23. Detection of the [O I] 63 $\mu$m emission line from the $z = 6.04$ quasar J2054-0005
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Ishii, Nozomi, Hashimoto, Takuya, Ferkinhoff, Carl, Rybak, Matus, Inoue, Akio K., Michiyama, Tomonari, Donevski, Darko, Fujimoto, Seiji, Salak, Dragan, Kuno, Nario, Matsuo, Hiroshi, Mawatari, Ken, Tamura, Yoichi, Izumi, Takuma, Nagao, Tohru, Nakazato, Yurina, Osone, Wataru, Sugahara, Yuma, Usui, Mitsutaka, Wakasugi, Koki, Yajima, Hidenobu, Bakx, Tom J. L. C., Fudamoto, Yoshinobu, Meyer, Romain A., Walter, Fabian, and Yoshida, Naoki
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Astrophysics - Astrophysics of Galaxies - Abstract
We report the highest-redshift detection of [O I] 63 $\mu$m from a luminous quasar, J2054-0005, at $z=6.04$ based on the Atacama Large Millimeter/sub-millimeter Array Band 9 observations. The [O I] 63 $\mu$m line luminosity is $(4.5\pm1.5) \times 10^{9}~L_{\rm \odot}$, corresponding to the [O I] 63 $\mu$m-to-far-infrared luminosity ratio of $\approx 6.7\times10^{-4}$, which is consistent with the value obtained in the local universe. Remarkably, [O I] 63 $\mu$m is as bright as [C II] 158 $\mu$m, resulting in the [O I]-to-[C II] line luminosity ratio of $1.3\pm0.5$. Based on a careful comparison of the luminosity ratios of [O I] 63 $\mu$m, [C II] 158 $\mu$m, and dust continuum emission to models of photo-dissociation regions, we find that J2054-0005 has a gas density log($n_{\rm H}$/cm$^{-3}$)$=3.7\pm0.3$ and an incident far-ultraviolet radiation field of log($G/G_{\rm 0}$)$= 3.0\pm0.1$, showing that [O I] 63 $\mu$m serves as an important coolant of the dense and warm gas in J2054-0005. A close examination of the [O I] and [C II] line profiles suggests that the [O I] line may be partially self-absorbed, however deeper observations are needed to verify this conclusion. Regardless, the gas density and incident radiation field are in a broad agreement with the values obtained in nearby star-forming galaxies and objects with [O I] 63 $\mu$m observations at $z=1-3$ with the Herschel Space Observatory. These results demonstrate the power of ALMA high-frequency observations targeting [O I] 63 $\mu$m to examine the properties of photo-dissociation regions in high-redshift galaxies., Comment: Submitted to PASJ. 5 figures and 3 tables. Comments are very welcome
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- 2024
24. Dominating Set Reconfiguration with Answer Set Programming
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Kato, Masato, Schaub, Torsten, Soh, Takehide, Tamura, Naoyuki, and Banbara, Mutsunori
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Computer Science - Artificial Intelligence - Abstract
The dominating set reconfiguration problem is defined as determining, for a given dominating set problem and two among its feasible solutions, whether one is reachable from the other via a sequence of feasible solutions subject to a certain adjacency relation. This problem is PSPACE-complete in general. The concept of the dominating set is known to be quite useful for analyzing wireless networks, social networks, and sensor networks. We develop an approach to solve the dominating set reconfiguration problem based on Answer Set Programming (ASP). Our declarative approach relies on a high-level ASP encoding, and both the grounding and solving tasks are delegated to an ASP-based combinatorial reconfiguration solver. To evaluate the effectiveness of our approach, we conduct experiments on a newly created benchmark set.
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- 2024
25. Dynamical and Atmospheric Characterization of the Substellar Companion HD 33632 Ab from Direct Imaging, Astrometry, and Radial-Velocity Data
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Morsy, Mona El, Currie, Thayne, Bovie, Danielle, Kuzuhara, Masayuki, Lacy, Brianna, Li, Yiting, Tobin, Taylor, Brandt, Timothy, Chilcote, Jeffrey, Guyon, Olivier, Groff, Tyler, Lozi, Julien, Vievard, Sebastien, Deo, Vincent, Skaf, Nour, Bouchy, Francois, Boisse, Isabelle, Dykes, Erica, Kasdin, N. J., and Tamura, Motohide
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Astrophysics - Earth and Planetary Astrophysics ,Astrophysics - Solar and Stellar Astrophysics - Abstract
We present follow-up SCExAO/CHARIS $H$ and $K$-band (R $\sim$ 70) high-contrast integral field spectroscopy and Keck/NIRC2 photometry of directly-imaged brown dwarf companion HD 33632 Ab and new radial-velocity data for the system from the SOPHIE spectrograph, complemented by Hipparcos and Gaia astrometry. These data enable more robust spectral characterization compared to lower-resolution spectra from the discovery paper and more than double the available astrometric and radial-velocity baseline. HD 33632 Ab's spectrum is well reproduced by a field L8.5--L9.5 dwarf. Using the Exo-REM atmosphere models, we derive a best-fit temperature, surface gravity and radius of $T_{\rm eff}$ = 1250 $K$, log(g) = 5, and $R$ = 0.97 $R_{\rm J}$ and a solar C/O ratio. Adding the SOPHIE radial-velocity data enables far tighter constraints on the companion's orbital properties (e.g. $i$=${46.6}_{-5.7}^{+2.9}$$^{o}$) and dynamical mass (${51.7}_{-2.5}^{+2.6}$$M_{\rm J}$) than derived from imaging data and \textit{Gaia} eDR3 astrometry data alone. HD 33632 Ab should be a prime target for multi-band imaging and spectroscopy with the James Webb Space Telescope and the Roman Space Telescope's Coronagraphic Instrument, shedding detailed light on HD 33632 Ab's clouds and chemistry and providing a key reference point for understanding young exoplanet atmospheres., Comment: 20 pages, 11 figures, 7 tables; submitted to AAS Journals
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- 2024
26. OpenUAS: Embeddings of Cities in Japan with Anchor Data for Cross-city Analysis of Area Usage Patterns
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Tamura, Naoki, Shoji, Kazuyuki, Katayama, Shin, Urano, Kenta, Yonezawa, Takuro, and Kawaguchi, Nobuo
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Computer Science - Machine Learning - Abstract
We publicly release OpenUAS, a dataset of area embeddings based on urban usage patterns, including embeddings for over 1.3 million 50-meter square meshes covering a total area of 3,300 square kilometers. This dataset is valuable for analyzing area functions in fields such as market analysis, urban planning, transportation infrastructure, and infection prediction. It captures the characteristics of each area in the city, such as office districts and residential areas, by employing an area embedding technique that utilizes location information typically obtained by GPS. Numerous area embedding techniques have been proposed, and while the public release of such embedding datasets is technically feasible, it has not been realized. One of the obstacles has been the integration of data from different cities and periods into a unified space without sharing raw location data. We address this issue by developing an anchoring method that establishes anchors within a shared embedding space. We publicly release this anchor dataset along with area embedding datasets from several periods in eight major Japanese cities. This dataset allows users to analyze urban usage patterns in Japanese cities and embed their urban dataset into the same embedding space using the anchoring method. Our key contributions include the development of the anchoring method, releasing area embedding datasets for Japanese cities, and providing tools for effective data utilization.
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- 2024
27. Relative Alignments Between Magnetic Fields, Velocity Gradients, and Dust Emission Gradients in NGC 1333
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Chen, Michael Chun-Yuan, Fissel, Laura M., Sadavoy, Sarah I., Rosolowsky, Erik, Doi, Yasuo, Arzoumanian, Doris, Bastien, Pierre, Coudé, Simon, Di Francesco, James, Friesen, Rachel, Furuya, Ray S., Hwang, Jihye, Inutsuka, Shu-ichiro, Johnstone, Doug, Karoly, Janik, Kwon, Jungmi, Kwon, Woojin, Gouellec, Valentin J. M. Le, Liu, Hong-Li, Mairs, Steve, Onaka, Takashi, Pattle, Kate, Rawlings, Mark G., Tahani, Mehrnoosh, Tamura, Motohide, and Wang, Jia-Wei
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Astrophysics - Astrophysics of Galaxies - Abstract
Magnetic fields play an important role in shaping and regulating star formation in molecular clouds. Here, we present one of the first studies examining the relative orientations between magnetic ($B$) fields and the dust emission, gas column density, and velocity centroid gradients on the 0.02 pc (core) scales, using the BISTRO and VLA+GBT observations of the NGC 1333 star-forming clump. We quantified these relative orientations using the Project Rayleigh Statistic (PRS) and found preferential global parallel alignment between the $B$ field and dust emission gradients, consistent with large-scale studies with Planck. No preferential global alignments, however, are found between the $B$ field and velocity gradients. Local PRS calculated for subregions defined by either dust emission or velocity coherence further revealed that the $B$ field does not preferentially align with dust emission gradients in most emission-defined subregions, except in the warmest ones. The velocity-coherent structures, on the other hand, also showed no preferred $B$ field alignments with velocity gradients, except for one potentially bubble-compressed region. Interestingly, the velocity gradient magnitude in NGC 1333 ubiquitously features prominent ripple-like structures that are indicative of magnetohydrodynamic (MHD) waves. Finally, we found $B$ field alignments with the emission gradients to correlate with dust temperature and anticorrelate with column density, velocity dispersion, and velocity gradient magnitude. The latter two anticorrelations suggest that alignments between gas structures and $B$ fields can be perturbed by physical processes that elevate velocity dispersion and velocity gradients, such as infall, accretions, and MHD waves., Comment: Accepted to the Monthly Notices of the Royal Astronomical Society Main Journal
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- 2024
28. Visible Photonic Lantern integration, characterization and on-sky testing on Subaru/SCExAO
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Vievard, Sébastien, Lallement, Manon, Leon-Saval, Sergio, Guyon, Olivier, Jovanovic, Nemanja, Huby, Elsa, Lacour, Sylvestre, Lozi, Julien, Deo, Vincent, Ahn, Kyohoon, Lucas, Miles, Currie, Thayne, Sallum, Steph, Fitzgerald, Michael P., Betters, Chris, Norris, Barnaby, Amezcua-Correa, Rodrigo, Yerolatsitis, Stephanos, Lin, Jon, Kim, Yoo-Jung, Gatkine, Pradip, Kotani, Takayuki, Tamura, Motohide, Martin, Guillermo, Goldsmith, Harry-Dean Kenchington, and Perrin, Guy
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Astrophysics - Instrumentation and Methods for Astrophysics - Abstract
A Photonic Lantern (PL) is a novel device that efficiently converts a multi-mode fiber into several single-mode fibers. When coupled with an extreme adaptive optics (ExAO) system and a spectrograph, PLs enable high throughput spectroscopy at high angular resolution. The Subaru Coronagraphic Extreme Adaptive Optics (SCExAO) system of the Subaru Telescope recently acquired a PL that converts its multi-mode input into 19 single-mode outputs. The single mode outputs feed a R~4,000 spectrograph optimized for the 600 to 760 nm wavelength range. We present here the integration of the PL on SCExAO, and study the device performance in terms of throughput, field of view, and spectral reconstruction. We also present the first on-sky demonstration of a Visible PL coupled with an ExAO system, showing a significant improvement of x12 in throughput compared to the use of a sole single-mode fiber. This work paves the way towards future high throughput photonics instrumentation at small angular resolution., Comment: Proceeding published in SPIE Astronomical Telescopes + Instrumentation (2024) - Paper number 13096-25
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- 2024
29. Commissioning of a compact multibend achromat lattice: A new 3 GeV synchrotron radiation facility
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Obara, Shuhei, Ueshima, Kota, Asaka, Takao, Hosaka, Yuji, Kan, Koichi, Nishimori, Nobuyuki, Aoki, Toshitaka, Asano, Hiroyuki, Haga, Koichi, Iba, Yuto, Ihara, Akira, Ito, Katsumasa, Iwashita, Taiki, Kadowaki, Masaya, Kanahama, Rento, Kobayashi, Hajime, Kobayashi, Hideki, Nishihara, Hideo, Nishikawa, Masaaki, Oikawa, Haruhiko, Saida, Ryota, Sakuraba, Keisuke, Sugimoto, Kento, Suzuki, Masahiro, Takahashi, Kouki, Takahashi, Shunya, Tanaka, Tatsuki, Tsuchiyama, Tsubasa, Yoshioka, Risa, Aoki, Tsuyoshi, Dewa, Hideki, Fujita, Takahiro, Kawase, Morihiro, Kiyomich, Akio, Hamano, Takashi, Masaki, Mitsuhiro, Masuda, Takemasa, Matsubara, Shinichi, Okada, Kensuke, Saji, Choji, Taniuchi, Tsutomu, Taniuchi, Yukiko, Ueda, Yosuke, Yamaguchi, Hiroshi, Yanagida, Kenichi, Fukami, Kenji, Hosoda, Naoyasu, Ishii, Miho, Itoga, Toshiro, Iwai, Eito, Magome, Tamotsu, Oishi, Masaya, Ohshima, Takashi, Kondo, Chikara, Sakurai, Tatsuyuki, Shoji, Masazumi, Sugimoto, Takashi, Takano, Shiro, Tamura, Kazuhiro, Watanabe, Takahiro, Tomai, Takato, Azumi, Noriyoshi, Inagaki, Takahiro, Maesaka, Hirokazu, Takahashi, Sunao, Tanaka, Takashi, Inoue, Shinobu, Kumazawa, Hirosuke, Moriya, Kazuki, Sakai, Kohei, Seno, Toshio, Sumitomo, Hiroshi, Takesako, Ryoichi, Tanaka, Shinichiro, Yamamoto, Ryo, Yokomachi, Kazutoshi, Yoshioka, Masamichi, Hara, Toru, Matsui, Sakuo, Hiraiwa, Toshihiko, Tanaka, Hitoshi, and Ego, Hiroyasu
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Physics - Accelerator Physics ,High Energy Physics - Experiment - Abstract
NanoTerasu, a new 3 GeV synchrotron light source in Japan, began user operation in April 2024. It provides high-brilliance soft to tender X-rays and covers a wide spectral range from ultraviolet to tender X-rays. Its compact storage ring with a circumference of 349 m is based on a four-bend achromat lattice to provide two straight sections in each cell for insertion devices with a natural horizontal emittance of 1.14 nm rad, which is small enough for soft X-rays users. The NanoTerasu accelerator incorporates several innovative technologies, including a full-energy injector C-band linear accelerator with a length of 110 m, an in-vacuum off-axis injection system, a four-bend achromat with B-Q combined bending magnets, and a TM020 mode accelerating cavity with built-in higher-order-mode dampers in the storage ring. This paper presents the accelerator machine commissioning over a half-year period and our model-consistent ring optics correction. The first user operation with a stored beam current of 160 mA is also reported. We summarize the storage ring parameters obtained from the commissioning. This is helpful for estimating the effective optical properties of synchrotron radiation at NanoTerasu., Comment: 30 pages, 24 figures, submitted to the journal
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- 2024
30. Smooth finite group actions on homology six-spheres with odd euler chracteristic fixed point sets
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Tamura, Shunsuke
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Mathematics - Geometric Topology - Abstract
In this paper, we prove that if a finite group acts smoothly and effectively on an integral homology six-sphere and the fixed point set has an odd Euler characteristic, then the acting group is isomorphic to either the alternating group on five letters, the symmetric group on five letters, or the Cartesian product of the alternating group on five letters and a group of order 2 and the fixed point set consists of precisely one point.
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- 2024
31. Evidence of Water Vapor in the Atmosphere of a Metal-Rich Hot Saturn with High-Resolution Transmission Spectroscopy
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Rafi, Sayyed A., Nugroho, Stevanus K., Tamura, Motohide, Nortmann, Lisa, and Sánchez-López, Alejandro
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Astrophysics - Earth and Planetary Astrophysics - Abstract
Transmission spectroscopy presents one of the most successful approaches for investigating the atmospheres of exoplanets. We analyzed the near-infrared high-resolution transmission spectrum of a hot Saturn, HD 149026 b, taken using CARMENES spectrograph ($\mathcal{R}\sim80,400$). We found evidence of H$_2$O at an S/N of $\sim$4.8. We also performed grid search using a Bayesian framework and constrained the orbital velocity $K_\mathrm{p}$ and rest velocity $V_{\mathrm{rest}}$ to $158.17^{+8.31}_{-7.90}$ $\mathrm{km\ s}^{-1}$ and $2.57^{+0.54}_{-0.57}$ $\mathrm{km\ s}^{-1}$, respectively. Whilst the retrieved $K_\mathrm{p}$ value is consistent with theoretical prediction, the retrieved $V_{\mathrm{rest}}$ value is highly red-shifted ($>$3-$\sigma$). This might be an indication of either anomalous atmospheric dynamics at play or an orbit with non-zero eccentricity. Additionally, we searched for HCN but no successful detection has been made possibly due to the relatively low S/N dataset. The detection of H$_2$O and subsequent abundance retrieval, coupled with analysis of other species such as CO at the $K$-band, for example, might help us to get some information about the atmospheric C/O ratio and metallicity, which in turn could give us some insight into the planet formation scenario., Comment: 22 pages, 15 figures, 1 table. Accepted for publication at AJ
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- 2024
32. Status of Xtend telescope onboard X-Ray Imaging and Spectroscopy Mission (XRISM)
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Mori, Koji, Tomida, Hiroshi, Nakajima, Hiroshi, Okajima, Takashi, Noda, Hirofumi, Uchida, Hiroyuki, Suzuki, Hiromasa, Kobayashi, Shogo Benjamin, Yoneyama, Tomokage, Hagino, Kouichi, Nobukawa, Kumiko, Tanaka, Takaaki, Murakami, Hiroshi, Uchiyama, Hideki, Nobukawa, Masayoshi, Matsumoto, Hironori, Tsuru, Takeshi, Yamauchi, Makoto, Hatsukade, Isamu, Odaka, Hirokazu, Kohmura, Takayoshi, Yamaoka, Kazutaka, Ishida, Manabu, Maeda, Yoshitomo, Hayashi, Takayuki, Tamura, Keisuke, Boissay-Malaquin, Rozenn, Sato, Toshiki, Yoshida, Tessei, Kanemaru, Yoshiaki, Hiraga, Junko, Dotani, Tadayasu, Ozaki, Masanobu, Tsunemi, Hiroshi, Inoue, Shun, Azuma, Ryuishi, Aoki, Yuma, Asahina, Yoh, Nakamura, Shotaro, Kamei, Takamitsu, Fukuda, Masahiro, Asakura, Kazunori, Yoshimoto, Marina, Ode, Yuichi, Hakamata, Tomohiro, Aoyagi, Mio, shima, Kohei, Ito, Yamato, Aoki, Daiki, Fujisawa, Kaito, Shimizu, Yasuyuki, Higuchi, Mayu, Miyazaki, Keitaro, Kusunoki, Kohei, Otsuka, Yoshinori, Yokosu, Haruhiko, Yonemaru, Wakana, Ichikawa, Kazuhiro, Nakano, Hanako, takemoto, Reo, Matsushima, Tsukasa, and Hayashida, Kiyoshi
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Astrophysics - Instrumentation and Methods for Astrophysics - Abstract
Xtend is one of the two telescopes onboard the X-ray imaging and spectroscopy mission (XRISM), which was launched on September 7th, 2023. Xtend comprises the Soft X-ray Imager (SXI), an X-ray CCD camera, and the X-ray Mirror Assembly (XMA), a thin-foil-nested conically approximated Wolter-I optics. A large field of view of $38^{\prime}\times38^{\prime}$ over the energy range from 0.4 to 13 keV is realized by the combination of the SXI and XMA with a focal length of 5.6 m. The SXI employs four P-channel, back-illuminated type CCDs with a thick depletion layer of 200 $\mu$m. The four CCD chips are arranged in a 2$\times$2 grid and cooled down to $-110$ $^{\circ}$C with a single-stage Stirling cooler. Before the launch of XRISM, we conducted a month-long spacecraft thermal vacuum test. The performance verification of the SXI was successfully carried out in a course of multiple thermal cycles of the spacecraft. About a month after the launch of XRISM, the SXI was carefully activated and the soundness of its functionality was checked by a step-by-step process. Commissioning observations followed the initial operation. We here present pre- and post-launch results verifying the Xtend performance. All the in-orbit performances are consistent with those measured on ground and satisfy the mission requirement. Extensive calibration studies are ongoing., Comment: 10 pages, 8 figures. Proceedings of SPIE Astronomical Telescopes and Instrumentation 2024
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- 2024
33. Gas conditions of a star-formation selected sample in the first billion years
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Bakx, Tom J. L. C., Algera, Hiddo S. B., Venemans, Bram, Sommovigo, Laura, Fujimoto, Seiji, Carniani, Stefano, Hagimoto, Masato, Hashimoto, Takuya, Inoue, Akio K., Salak, Dragan, Serjeant, Stephen, Vallini, Livia, Eales, Stephen, Ferrara, Andrea, Fudamoto, Yoshinobu, Imamura, Chihiro, Inoue, Shigeki, Knudsen, Kirsten K., Matsuo, Hiroshi, Sugahara, Yuma, Tamura, Yoichi, Taniguchi, Akio, and Yamanaka, Satoshi
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Astrophysics - Astrophysics of Galaxies - Abstract
We present Atacama Large Millimetre/submillimetre Array (ALMA) observations of the [O$_{\rm III}$] 88 $\mu$m emission of a sample of thirteen galaxies at $z$ = 6 to 7.6 selected as [C$_{\rm II}$]-emitting companion sources of quasars. To disentangle the origins of the luminous Oxygen line in the $z$ > 6 Universe, we looked at emission-line galaxies that are selected through an excellent star-formation tracer [C$_{\rm II}$] with star-formation rates between 9 and 162 M$_{\odot}$/yr. Direct observations reveal [O$_{\rm III}$] emission in just a single galaxy (L$_{\rm [O_{\rm III}]}$/L$_{\rm [C_{\rm II}]}$ = 2.3), and a stacked image shows no [O$_{\rm III}$] detection, providing deep upper limits on the L$_{\rm [O_{\rm III}]}$/L$_{\rm [C_{\rm II}]}$ ratios in the $z > 6$ Universe (L$_{\rm [O_{\rm III}]}$/L$_{\rm [C_{\rm II}]}$ < 1.2 at 3${\sigma}$). While the fidelity of this sample is high, no obvious optical/near-infrared counterpart is seen in the JWST imaging available for four galaxies. Additionally accounting for low-redshift CO emitters, line stacking shows that our sample-wide result remains robust: The enhanced L$_{\rm [O_{\rm III}]}$/L$_{\rm [C_{\rm II}]}$ reported in the first billion years of the Universe is likely due to the selection towards bright, blue Lyman-break galaxies with high surface star-formation rates or young stellar populations. The deep upper limit on the rest-frame 90 $\mu$m continuum emission (< 141 $\mu$Jy at 3${\sigma}$), implies a low average dust temperature (T$_{\rm dust}$ < 30K) and high dust mass (M$_{\rm dust}$ ~ 10$^8$ M$_{\odot}$). As more normal galaxies are explored in the early Universe, synergy between JWST and ALMA is fundamental to further investigate the ISM properties of the a broad range of samples of high-$z$ galaxies., Comment: 20 pages; 13 figures; accepted for publication in MNRAS
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- 2024
34. JWST, ALMA, and Keck Spectroscopic Constraints on the UV Luminosity Functions at z~7-14: Clumpiness and Compactness of the Brightest Galaxies in the Early Universe
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Harikane, Yuichi, Inoue, Akio K., Ellis, Richard S., Ouchi, Masami, Nakazato, Yurina, Yoshida, Naoki, Ono, Yoshiaki, Sun, Fengwu, Sato, Riku A., Fujimoto, Seiji, Kashikawa, Nobunari, McLeod, Derek J., Perez-Gonzalez, Pablo G., Sawicki, Marcin, Sugahara, Yuma, Xu, Yi, Yamanaka, Satoshi, Carnall, Adam C., Cullen, Fergus, Dunlop, James S., Egami, Eiichi, Grogin, Norman, Isobe, Yuki, Koekemoer, Anton M., Laporte, Nicolas, Lee, Chien-Hsiu, Magee, Dan, Matsuo, Hiroshi, Matsuoka, Yoshiki, Mawatari, Ken, Nakajima, Kimihiko, Nakane, Minami, Tamura, Yoichi, Umeda, Hiroya, and Yanagisawa, Hiroto
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Astrophysics - Astrophysics of Galaxies - Abstract
We present the number densities and physical properties of the bright galaxies spectroscopically confirmed at $z\sim7-14$. Our sample is composed of 53 galaxies at $z_\mathrm{spec}\sim7-14$, including recently-confirmed galaxies at $z_\mathrm{spec}=12.34-14.32$ with JWST, as well as new confirmations at $z_\mathrm{spec}=6.583-7.643$ with $-24< M_\mathrm{UV}< -21$ mag using ALMA and Keck. Our JWST/NIRSpec observations have also revealed that very bright galaxy candidates at $z\sim10-13$ identified from ground-based telescope images before JWST are passive galaxies at $z\sim3-4$, emphasizing the necessity of strict screening and spectroscopy in the selection of the brightest galaxies at $z>10$. The UV luminosity functions derived from these spectroscopic results are consistent with a double power-law function, showing tensions with theoretical models at the bright end. To understand the origin of the overabundance of bright galaxies, we investigate their morphologies using JWST/NIRCam high-resolution images obtained in various surveys including PRIMER and COSMOS-Web. We find that $\sim70\%$ of the bright galaxies at $z\sim7$ exhibit clumpy morphologies with multiple sub-components, suggesting merger-induced starburst activity, which is consistent with SED fitting results showing bursty star formation histories. At $z\gtrsim10$, bright galaxies are classified into two types of galaxies; extended ones with weak high-ionization emission lines, and compact ones with strong high-ionization lines including NIV]$\lambda$1486, indicating that at least two different processes (e.g., merger-induced starburst and compact star formation/AGN) are shaping the physical properties of the brightest galaxies at $z\gtrsim10$ and are responsible for their overabundance., Comment: 32 pages, 22 figures, submitted to ApJ
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- 2024
35. The VISTA Variables in the V\'ia L\'actea eXtended (VVVX) ESO public survey: Completion of the observations and legacy
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Saito, R. K., Hempel, M., Alonso-García, J., Lucas, P. W., Minniti, D., Alonso, S., Baravalle, L., Borissova, J., Caceres, C., Chené, A. N., Cross, N. J. G., Duplancic, F., Garro, E. R., Gómez, M., Ivanov, V. D., Kurtev, R., Luna, A., Majaess, D., Navarro, M. G., Pullen, J. B., Rejkuba, M., Sanders, J. L., Smith, L. C., Albino, P. H. C., Alonso, M. V., Amôres, E. B., Angeloni, R., Arias, J. I., Arnaboldi, M., Barbuy, B., Bayo, A., Beamin, J. C., Bedin, L. R., Bellini, A., Benjamin, R. A., Bica, E., Bonatto, C. J., Botan, E., Braga, V. F., Brown, D. A., Cabral, J. B., Camargo, D., Garatti, A. Caratti o, Carballo-Bello, J. A., Catelan, M., Chavero, C., Chijani, M. A., Clariá, J. J., Coldwell, G. V., Peña, C. Contreras, Ramos, R. Contreras, Corral-Santana, J. M., Cortés, C. C., Cortés-Contreras, M., Cruz, P., Daza-Perilla, I. V., Debattista, V. P., Dias, B., Donoso, L., D'Souza, R., Emerson, J. P., Federle, S., Fermiano, V., Fernandez, J., Fernández-Trincado, J. G., Ferreira, T., Lopes, C. E. Ferreira, Firpo, V., Flores-Quintana, C., Fraga, L., Froebrich, D., Galdeano, D., Gavignaud, I., Geisler, D., Gerhard, O. E., Gieren, W., Gonzalez, O. A., Gramajo, L. V., Gran, F., Granitto, P. M., Griggio, M., Guo, Z., Gurovich, S., Hilker, M., Jones, H. R. A., Kammers, R., Kuhn, M. A., Kumar, M. S . N., Kundu, R., Lares, M., Libralato, M., Lima, E., Maccarone, T. J., Cortés, P. Marchant, Martin, E. L., Masetti, N., Matsunaga, N., Mauro, F., McDonald, I., Mejías, A., Mesa, V., Milla-Castro, F. P., Minniti, J. H., Bidin, C. Moni, Montenegro, K., Morris, C., Motta, V., Navarete, F., Molina, C. Navarro, Nikzat, F., Castellón, J. L. Nilo, Obasi, C., Ortigoza-Urdaneta, M., Palma, T., Parisi, C., Ramírez, K. Pena, Pereyra, L., Perez, N., Petralia, I., Pichel, A., Pignata, G., Alegría, S. Ramírez, Rojas, A. F., Rojas, D., Roman-Lopes, A., Rovero, A. C., Saroon, S., Schmidt, E. O., Schröder, A. C., Schultheis, M., Sgró, M. A., Solano, E., Soto, M., Stecklum, B., Steeghs, D., Tamura, M., Tissera, P., Valcarce, A. A. R., Valotto, C. A., Vasquez, S., Villalon, C., Villanova, S., Cádiz, F. Vivanco, Bacigalupo, R. Zelada, Zijlstra, A., and Zoccali, M.
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Astrophysics - Astrophysics of Galaxies ,Astrophysics - Solar and Stellar Astrophysics - Abstract
The ESO public survey VISTA Variables in the V\'ia L\'actea (VVV) surveyed the inner Galactic bulge and the adjacent southern Galactic disk from $2009-2015$. Upon its conclusion, the complementary VVV eXtended (VVVX) survey has expanded both the temporal as well as spatial coverage of the original VVV area, widening it from $562$ to $1700$ sq. deg., as well as providing additional epochs in $JHK_{\rm s}$ filters from $2016-2023$. With the completion of VVVX observations during the first semester of 2023, we present here the observing strategy, a description of data quality and access, and the legacy of VVVX. VVVX took $\sim 2000$ hours, covering about 4% of the sky in the bulge and southern disk. VVVX covered most of the gaps left between the VVV and the VISTA Hemisphere Survey (VHS) areas and extended the VVV time baseline in the obscured regions affected by high extinction and hence hidden from optical observations. VVVX provides a deep $JHK_{\rm s}$ catalogue of $\gtrsim 1.5\times10^9$ point sources, as well as a $K_{\rm s}$ band catalogue of $\sim 10^7$ variable sources. Within the existing VVV area, we produced a $5D$ map of the surveyed region by combining positions, distances, and proper motions of well-understood distance indicators such as red clump stars, RR Lyrae, and Cepheid variables. In March 2023 we successfully finished the VVVX survey observations that started in 2016, an accomplishment for ESO Paranal Observatory upon 4200 hours of observations for VVV+VVVX. The VVV+VVVX catalogues complement those from the Gaia mission at low Galactic latitudes and provide spectroscopic targets for the forthcoming ESO high-multiplex spectrographs MOONS and 4MOST., Comment: 17 pages, 11 figures (+ appendix). Accepted for publication in Astronomy and Astrophysics in section 14: Catalogs and data
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- 2024
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36. Data-driven study of the enthalpy of mixing in the liquid phase
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Deffrennes, Guillaume, Hallstedt, Bengt, Abe, Taichi, Bizot, Quentin, Fischer, Evelyne, Joubert, Jean-Marc, Terayama, Kei, and Tamura, Ryo
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Condensed Matter - Materials Science ,Physics - Computational Physics - Abstract
The enthalpy of mixing in the liquid phase is a thermodynamic property reflecting interactions between elements that is key to predict phase transformations. Widely used models exist to predict it, but they have never been systematically evaluated. To address this, we collect a large amount of enthalpy of mixing data in binary liquids from a review of about 1000 thermodynamic evaluations. This allows us to clarify the prediction accuracy of Miedema's model which is state-of-the-art. We show that more accurate predictions can be obtained from a machine learning model based on LightGBM, and we provide them in 2415 binary systems. The data we collect also allows us to evaluate another empirical model to predict the excess heat capacity that we apply to 2211 binary liquids. We then extend the data collection to ternary metallic liquids and find that, when mixing is exothermic, extrapolations from the binary systems by Muggianu's model systematically lead to slight overestimations of roughly 10% close to the equimolar composition. Therefore, our LightGBM model can provide reasonable estimates for ternary alloys and, by extension, for multicomponent alloys. Our findings extracted from rich datasets can be used to feed thermodynamic, empirical and machine learning models for material development., Comment: Manuscript: 27 pages, 5 figures ; Supplementary notes: 3 pages, 5 figures
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- 2024
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37. A 10.24-GHz-wide digital spectrometer array system for LMT-FINER: system design and laboratory performance verification
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Hagimoto, Masato, Taniguchi, Akio, Tamura, Yoichi, Okauchi, Norika, Kawamoto, Hiroaki, Nakajima, Taku, Hikosaka, Takumi, Harada, Kenichi, Taniguchi, Toru, Kamazaki, Takeshi, Sakai, Takeshi, Tanaka, Kunihiko, and Kawabe, Ryohei
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Astrophysics - Instrumentation and Methods for Astrophysics - Abstract
For efficient spectroscopic redshift identification of early galaxies in the northern hemisphere, we aim to combine the Large Millimeter Telescope (LMT) with a wide-band heterodyne receiver, FINER, which will cover radio frequencies of 120--360 GHz and offer a 3--21 GHz intermediate frequency (IF) per sideband and polarization. To take full advantage of such wide IFs, we present a novel 10.24-GHz-wide digital spectrometer, DRS4 (Elecs Industry Co., Ltd.). It incorporates 20.48 Gsps samplers with an FPGA-based digital signal processing module. To mitigate the noise contamination from the image sideband, it is equipped with a digital sideband separation function to improve the sideband rejection up to 25 dB. Laboratory performance evaluations show that it exhibits an Allan time of at least ~100 s and a total power dynamic range of at least 7 dB. These results demonstrate its capability of instantaneously wide-band spectroscopy toward high-redshift galaxies with position-switching observations., Comment: 10 pages, 7 figures, Proceedings paper presented in SPIE Astronomical Telescope and Instrumentation 2024
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- 2024
38. FINER: Far-Infrared Nebular Emission Receiver for the Large Millimeter Telescope
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Tamura, Yoichi, Sakai, Takeshi, Kawabe, Ryohei, Kojima, Takafumi, Taniguchi, Akio, Takekoshi, Tatsuya, Kang, Haoran, Shan, Wenlei, Hagimoto, Masato, Okauchi, Norika, Tetsuka, Airi, Inoue, Akio K., Kohno, Kotaro, Tanaka, Kunihiko, Bakx, Tom J. L. C., Fudamoto, Yoshinobu, Fujita, Kazuyuki, Harikane, Yuichi, Hashimoto, Takuya, Hatsukade, Bunyo, Hughes, David H., Iino, Takahiro, Kimura, Yuki, Maezawa, Hiroyuki, Matsuda, Yuichi, Mawatari, Ken, Nakajima, Taku, Nakatsubo, Shunichi, Oshima, Tai, Sagawa, Hideo, Schloerb, F. Peter, Takahashi, Shigeru, Taniguchi, Kotomi, Tsujita, Akiyoshi, Umehata, Hideki, Yonetsu, Teppei, and Yun, Min S.
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Astrophysics - Instrumentation and Methods for Astrophysics - Abstract
Unveiling the emergence and prevalence of massive/bright galaxies during the epoch of reionization and beyond, within the first 600 million years of the Universe, stands as a pivotal pursuit in astronomy. Remarkable progress has been made by JWST in identifying an immense population of bright galaxies, which hints at exceptionally efficient galaxy assembly processes. However, the underlying physical mechanisms propelling their rapid growth remain unclear. With this in mind, millimeter and submillimeter-wave spectroscopic observations of redshifted far-infrared spectral lines, particularly the [O III] 88 micron and [C II] 158 micron lines, offers a crucial pathway to address this fundamental query. To this end, we develop a dual-polarization sideband-separating superconductor-insulator-superconductor (SIS) mixer receiver, FINER, for the Large Millimeter Telescope (LMT) situated in Mexico. Harnessing advancements from ALMA's wideband sensitivity upgrade (WSU) technology, FINER covers radio frequencies spanning 120-360 GHz, delivering an instantaneous intermediate frequency (IF) of 3-21 GHz per sideband per polarization, which is followed by a set of 10.24 GHz-wide digital spectrometers. At 40% of ALMA's light-collecting area, the LMT's similar atmospheric transmittance and FINER's 5 times wider bandwidth compared to ALMA culminate in an unparalleled spectral scanning capability in the northern hemisphere, paving the way for finer spectral-resolution detection of distant galaxies., Comment: 12 pages, 8 figures, and 3 tables. Proceedings paper presented in SPIE Astronomical Telescope and Instrumentation 2024
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- 2024
39. Development Status of Wideband Millimeter-Wave Receivers for LMT-FINER
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Kang, Haoran, Kojima, Takafumi, Sakai, Takeshi, Tamura, Yoichi, Tetsuka, Airi, Masui, Sho, and Takekoshi, Tatsuya
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Astrophysics - Instrumentation and Methods for Astrophysics - Abstract
Spectroscopic observations of the far-infrared [O III] and [C II] lines present a pathway to explore the mechanisms of the emergence of massive galaxies in the epoch of reionization and beyond, which is one of the most fundamental questions in astronomy. To address this question, the Far-Infrared Nebular Emission Receiver (FINER) project is developing two wideband dual-polarization sideband-separating heterodyne receivers at 120--210 GHz and 210--360 GHz for the Large Millimeter Telescope (LMT) in Mexico. Compared with Atacama Large Millimeter/submillimeter Array (ALMA), LMT provides 40% of ALMA's light-collecting area and a similar atmospheric transmittance, but FINER plans to have an instantaneous intermediate frequency (IF) of 3--21 GHz per sideband per polarization which is five times wider than current ALMA's bandwidth. Therefore, FINER is going to offer cutting-edge spectral scanning capability in the next several years. The project is currently in an active development phase. In this proceeding, the latest development status for FINER, including the optics, wideband waveguide components as well as low-noise superconductor-insulator-superconductor (SIS) mixers is reported., Comment: 14 pages, 8 figures, 1 table. Proceeding paper presented in SPIE Astronomical Telescope and Instrumentation 2024
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- 2024
40. Collapse of a quantum vortex in an attractive two-dimensional Bose gas
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Banerjee, Sambit, Zhou, Kai, Tiwari, Shiva Kant, Tamura, Hikaru, Li, Rongjie, Kevrekidis, Panayotis, Mistakidis, Simeon I., Walther, Valentin, and Hung, Chen-Lung
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Condensed Matter - Quantum Gases - Abstract
We experimentally and numerically study the collapse dynamics of a quantum vortex in a two-dimensional atomic superfluid following a fast interaction ramp from repulsion to attraction. We find the conditions and time scales for a superfluid vortex to radially converge into a quasi-stationary density profile, demonstrating the first spontaneous formation of a vortex soliton in an atomic Bose gas. We record an emergent universal dynamics of an azimuthal modulational instability, which amplifies initial density perturbations and leads to the eventual splitting of a vortex soliton or direct fragmentation of a superfluid into disordered, but roughly circular arrays of Townes soliton-like wavepackets. Our study sets the stage for exploring universal out-of-equilibrium dynamics of vortex quantum matter quenched to attractive interactions.
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- 2024
41. Detection of an Earth-sized exoplanet orbiting the nearby ultracool dwarf star SPECULOOS-3
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Gillon, Michaël, Pedersen, Peter P., Rackham, Benjamin V., Dransfield, Georgina, Ducrot, Elsa, Barkaoui, Khalid, Burdanov, Artem Y., Schroffenegger, Urs, Chew, Yilen Gómez Maqueo, Lederer, Susan M., Alonso, Roi, Burgasser, Adam J., Howell, Steve B., Narita, Norio, de Wit, Julien, Demory, Brice-Olivier, Queloz, Didier, Triaud, Amaury H. M. J., Delrez, Laetitia, Jehin, Emmanuël, Hooton, Matthew J., Garcia, Lionel J., Muñoz, Clàudia Jano, Murray, Catriona A., Pozuelos, Francisco J., Sebastian, Daniel, Timmermans, Mathilde, Thompson, Samantha J., Aceituno, Jesús, Aganze, Christian, Amado, Pedro J., Baycroft, Thomas, Benkhaldoun, Zouhair, Berardo, David, Bolmont, Emeline, Clark, Catherine A., Davis, Yasmin T., Davoudi, Fatemeh, de Beurs, Zoë L., de Leon, Jerome P., Ikoma, Masahiro, Ikuta, Kai, Isogai, Keisuke, Fukuda, Izuru, Fukui, Akihiko, Gerasimov, Roman, Ghachoui, Mourad, Günther, Maximilian N., Hasler, Samantha, Hayashi, Yuya, Heng, Kevin, Hu, Renyu, Kagetani, Taiki, Kawai, Yugo, Kawauchi, Kiyoe, Kitzmann, Daniel, Koll, Daniel D. B., Lendl, Monika, Livingston, John H., Lyu, Xintong, Valdés, Erik A. Meier, Mori, Mayuko, McCormac, James J., Murgas, Felipe, Niraula, Prajwal, Pallé, Enric, Plauchu-Frayn, Ilse, Rebolo, Rafael, Sabin, Laurence, Schackey, Yannick, Schanche, Nicole, Selsis, Franck, Sota, Alfredo, Stalport, Manu, Standing, Matthew R., Stassun, Keivan G., Tamura, Motohide, Theissen, Christopher A., Turbet, Martin, Van Grootel, Valérie, Varas, Roberto, Watanabe, Noriharu, and Lang, Francis Zong
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Astrophysics - Earth and Planetary Astrophysics - Abstract
Located at the bottom of the main sequence, ultracool dwarf stars are widespread in the solar neighbourhood. Nevertheless, their extremely low luminosity has left their planetary population largely unexplored, and only one of them, TRAPPIST-1, has so far been found to host a transiting planetary system. In this context, we present the SPECULOOS project's detection of an Earth-sized planet in a 17 h orbit around an ultracool dwarf of M6.5 spectral type located 16.8 pc away. The planet's high irradiation (16 times that of Earth) combined with the infrared luminosity and Jupiter-like size of its host star make it one of the most promising rocky exoplanet targets for detailed emission spectroscopy characterization with JWST. Indeed, our sensitivity study shows that just ten secondary eclipse observations with the Mid-InfraRed Instrument/Low-Resolution Spectrometer on board JWST should provide strong constraints on its atmospheric composition and/or surface mineralogy.
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- 2024
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42. Endoscopic ultrasound-guided hepaticogastrostomy vs. antegrade metal stent placement keeping an access route in patients with malignant biliary obstruction
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Itonaga, Masahiro, Ashida, Reiko, Hatamaru, Keiichi, Yamashita, Yasunobu, Kawaji, Yuki, Tamura, Takashi, Emori, Tomoya, Shishimoto, Takahiro, Koutani, Hiromu, Tamura, Takaaki, Nakahata, Akiya, Yamazaki, Hirofumi, and Kitano, Masayuki
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- 2024
- Full Text
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43. Local strain inhomogeneities during electrical triggering of a metal-insulator transition revealed by X-ray microscopy.
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Salev, Pavel, Kisiel, Elliot, Sasaki, Dayne, Gunn, Brandon, He, Wei, Feng, Mingzhen, Li, Junjie, Tamura, Nobumichi, Poudyal, Ishwor, Islam, Zahirul, Takamura, Yayoi, Frano, Alex, and Schuller, Ivan
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X-ray microdiffraction ,dark-field X-ray microscopy ,in operando microscopy ,metal–insulator transition ,resistive switching - Abstract
Electrical triggering of a metal-insulator transition (MIT) often results in the formation of characteristic spatial patterns such as a metallic filament percolating through an insulating matrix or an insulating barrier splitting a conducting matrix. When MIT triggering is driven by electrothermal effects, the temperature of the filament or barrier can be substantially higher than the rest of the material. Using X-ray microdiffraction and dark-field X-ray microscopy, we show that electrothermal MIT triggering leads to the development of an inhomogeneous strain profile across the switching device, even when the material does not undergo a pronounced, discontinuous structural transition coinciding with the MIT. Diffraction measurements further reveal evidence of unique features associated with MIT triggering including lattice distortions, tilting, and twinning, which indicate structural nonuniformity of both low- and high-resistance regions inside the switching device. Such lattice deformations do not occur under equilibrium, zero-voltage conditions, highlighting the qualitative difference between states achieved through increasing temperature and applying voltage in nonlinear electrothermal materials. Electrically induced strain, lattice distortions, and twinning could have important contributions in the MIT triggering process and drive the material into nonequilibrium states, providing an unconventional pathway to explore the phase space in strongly correlated electronic systems.
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- 2024
44. Work in Progress: Fostering the Development of Engineering Identity in First-Year Women Engineering Students Through First-Year Seminars
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Tamura, Angelika, Chan, Tiffany, and Wang, Xianglong
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- 2024
45. In situ X-ray and IR probes relevant to Earth science at the Advanced Light Source at Lawrence Berkeley Laboratory
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Kunz, Martin, Armstrong, Katherine, Barnard, Harold, Bechtel, Hans A, Couper, Samantha C, Kalkan, Bora, Lisabeth, Harry, MacDowell, Alastair A, Miyagi, Lowell, Parkinson, Dilworth Y, Tamura, Nobumichi, and Williams, Quentin
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Earth Sciences ,Geology ,Synchrotron ,In situ X-ray diffraction ,In situ IR spectroscopy ,In situ X-ray tomography ,Geochemistry ,Materials Engineering ,Geochemistry & Geophysics - Abstract
Access to synchrotron X-ray facilities has become an important aspect for many disciplines in experimental Earth science. This is especially important for studies that rely on probing samples in situ under natural conditions different from the ones found at the surface of the Earth. The non-ambient condition Earth science program at the Advanced Light Source (ALS), Lawrence Berkeley National Laboratory, offers a variety of tools utilizing the infra-red and hard X-ray spectrum that allow Earth scientists to probe Earth and environmental materials at variable conditions of pressure, stress, temperature, atmospheric composition, and humidity. These facilities are important tools for the user community in that they offer not only considerable capacity (non-ambient condition diffraction) but also complementary (IR spectroscopy, microtomography), and in some cases unique (Laue microdiffraction) instruments. The availability of the ALS’ in situ probes to the Earth science community grows especially critical during the ongoing dark time of the Advanced Photon Source in Chicago, which massively reduces available in situ synchrotron user time in North America.
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- 2024
46. Stressful crystal histories recorded around melt inclusions in volcanic quartz
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Cadena, Tyler, Manga, Michael, Befus, Kenneth, and Tamura, Nobumichi
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Earth Sciences ,Geochemistry ,Geology ,Geophysics ,Residual stress ,Plastic strain ,Laue microdiffraction ,Melt inclusions ,Quartz ,Fragmentation ,Other Earth Sciences ,Energy ,Resources engineering and extractive metallurgy - Abstract
Magma ascent and eruption are driven by a set of internally and externally generated stresses that act upon the magma. We present microstructural maps around melt inclusions in quartz crystals from six large rhyolitic eruptions using synchrotron Laue X-ray microdiffraction to quantify elastic residual strain and stress. We measure plastic strain using average diffraction peak width and lattice misorientation, highlighting dislocations and subgrain boundaries. Quartz crystals across studied magma systems preserve similar and relatively small magnitudes of elastic residual stress (mean 53–135 MPa, median 46–116 MPa) in comparison to the strength of quartz (~ 10 GPa). However, the distribution of strain in the lattice around inclusions varies between samples. We hypothesize that dislocation and twin systems may be established during compaction of crystal-rich magma, which affects the magnitude and distribution of preserved elastic strains. Given the lack of stress-free haloes around faceted inclusions, we conclude that most residual strain and stress was imparted after inclusion faceting. Fragmentation may be one of the final strain events that superimposes stresses of ~ 100 MPa across all studied crystals. Overall, volcanic quartz crystals preserve complex, overprinted deformation textures indicating that quartz crystals have prolonged deformation histories throughout storage, fragmentation, and eruption.
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- 2024
47. An Integrated Deposition and Passivation Strategy for Controlled Crystallization of 2D/3D Halide Perovskite Films
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Kodalle, Tim, Byranvand, Malekshahi, Goudreau, Meredith, Das, Chittaranjan, Roy, Rajarshi, Kot, Małgorzata, Briesenick, Simon, Zohdi, Mohammadreza, Rai, Monika, Tamura, Nobumichi, Flege, Jan Ingo, Hempel, Wolfram, Sutter‐Fella, Carolin M, and Saliba, Michael
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Macromolecular and Materials Chemistry ,Chemical Sciences ,Physical Chemistry ,Engineering ,Materials Engineering ,2D/3D perovskites ,crystallization ,in situ characterization ,stability ,Physical Sciences ,Nanoscience & Nanotechnology ,Chemical sciences ,Physical sciences - Abstract
This work introduces a simplified deposition procedure for multidimensional (2D/3D) perovskite thin films, integrating a phenethylammonium chloride (PEACl)-treatment into the antisolvent step when forming the 3D perovskite. This simultaneous deposition and passivation strategy reduces the number of synthesis steps while simultaneously stabilizing the halide perovskite film and improving the photovoltaic performance of resulting solar cell devices to 20.8%. Using a combination of multimodal in situ and additional ex situ characterizations, it is demonstrated that the introduction of PEACl during the perovskite film formation slows down the crystal growth process, which leads to a larger average grain size and narrower grain size distribution, thus reducing carrier recombination at grain boundaries and improving the device's performance and stability. The data suggests that during annealing of the wet film, the PEACl diffuses to the surface of the film, forming hydrophobic (quasi-)2D structures that protect the bulk of the perovskite film from humidity-induced degradation.
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- 2024
48. A SARS-CoV-2 Interaction Dataset and VHH Sequence Corpus for Antibody Language Models
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Tsuruta, Hirofumi, Yamazaki, Hiroyuki, Maeda, Ryota, Tamura, Ryotaro, and Imura, Akihiro
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Computer Science - Machine Learning ,Quantitative Biology - Genomics - Abstract
Antibodies are crucial proteins produced by the immune system to eliminate harmful foreign substances and have become pivotal therapeutic agents for treating human diseases. To accelerate the discovery of antibody therapeutics, there is growing interest in constructing language models using antibody sequences. However, the applicability of pre-trained language models for antibody discovery has not been thoroughly evaluated due to the scarcity of labeled datasets. To overcome these limitations, we introduce AVIDa-SARS-CoV-2, a dataset featuring the antigen-variable domain of heavy chain of heavy chain antibody (VHH) interactions obtained from two alpacas immunized with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike proteins. AVIDa-SARS-CoV-2 includes binary labels indicating the binding or non-binding of diverse VHH sequences to 12 SARS-CoV-2 mutants, such as the Delta and Omicron variants. Furthermore, we release VHHCorpus-2M, a pre-training dataset for antibody language models, containing over two million VHH sequences. We report benchmark results for predicting SARS-CoV-2-VHH binding using VHHBERT pre-trained on VHHCorpus-2M and existing general protein and antibody-specific pre-trained language models. These results confirm that AVIDa-SARS-CoV-2 provides valuable benchmarks for evaluating the representation capabilities of antibody language models for binding prediction, thereby facilitating the development of AI-driven antibody discovery. The datasets are available at https://datasets.cognanous.com.
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- 2024
49. Finding Induced Subgraphs from Graphs with Small Mim-Width
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Otachi, Yota, Suzuki, Akira, and Tamura, Yuma
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Computer Science - Data Structures and Algorithms - Abstract
In the last decade, algorithmic frameworks based on a structural graph parameter called mim-width have been developed to solve generally NP-hard problems. However, it is known that the frameworks cannot be applied to the Clique problem, and the complexity status of many problems of finding dense induced subgraphs remains open when parameterized by mim-width. In this paper, we investigate the complexity of the problem of finding a maximum induced subgraph that satisfies prescribed properties from a given graph with small mim-width. We first give a meta-theorem implying that various induced subgraph problems are NP-hard for bounded mim-width graphs. Moreover, we show that some problems, including Clique and Induced Cluster Subgraph, remain NP-hard even for graphs with (linear) mim-width at most 2. In contrast to the intractability, we provide an algorithm that, given a graph and its branch decomposition with mim-width at most 1, solves Induced Cluster Subgraph in polynomial time. We emphasize that our algorithmic technique is applicable to other problems such as Induced Polar Subgraph and Induced Split Subgraph. Since a branch decomposition with mim-width at most 1 can be constructed in polynomial time for block graphs, interval graphs, permutation graphs, cographs, distance-hereditary graphs, convex graphs, and their complement graphs, our positive results reveal the polynomial-time solvability of various problems for these graph classes., Comment: To appear in the proceedings of the 19th Scandinavian Symposium on Algorithm Theory (SWAT 2024)
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- 2024
50. Text-Based Correlation Matrix in Multi-Asset Allocation
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Nakayama, Yasuhiro, Sawaki, Tomochika, Furuya, Issei, and Tamura, Shunsuke
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Computer Science - Computation and Language - Abstract
The purpose of this study is to estimate the correlation structure between multiple assets using financial text analysis. In recent years, as the background of elevating inflation in the global economy and monetary policy tightening by central banks, the correlation structure between assets, especially interest rate sensitivity and inflation sensitivity, has changed dramatically, increasing the impact on the performance of investors' portfolios. Therefore, the importance of estimating a robust correlation structure in portfolio management has increased. On the other hand, the correlation coefficient using only the historical price data observed in the financial market is accompanied by a certain degree of time lag, and also has the aspect that prediction errors can occur due to the nonstationarity of financial time series data, and that the interpretability from the viewpoint of fundamentals is a little poor when a phase change occurs. In this study, we performed natural language processing on news text and central bank text to verify the prediction accuracy of future correlation coefficient changes. As a result, it was suggested that this method is useful in comparison with the prediction from ordinary time series data., Comment: 4 pages, 4 figures, 1 tables
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- 2024
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