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2,050 results on '"Yokoyama, S."'

2. Electromagnetic probes of primordial black holes as dark matter

Author

Ali-Haimoud, Y., Clesse, S., Garcia-Bellido, J., Kashlinsky, A., Wyrzykowski, L., Achucarro, A., Amendola, L., Annis, J., Arbey, A., Arendt, R. G., Atrio-Barandela, F., Bellomo, N., Belotsky, K., Bernal, J-L., Bird, S., Bozza, V., Byrnes, C., Novati, S. Calchi, Calore, F., Carr, B. J., Chluba, J., Cholis, I., Cieplak, A., Cole, P., Dalianis, I., Davis, A-C., Davis, T., De Luca, V., Dvorkin, I., Emparan, R., Ezquiaga, J-M., Fleury, P., Franciolini, G., Gaggero, D., Georg, J., Germani, C., Giudice, G-F., Goobar, A., Hasinger, G., Hector, A., Hundertmark, M ., Hutsi, G., Jansen, R., Kamionkowski, M., Kawasaki, M., Kazanas, D., Kehagias, A., Khlopov, M., Knebe, A., Kohri, K., Koushiappas, S., Kovetz, E., Kuhnel, F., MacGibbon, J., Marzola, L., Mediavilla, E., Meszaros, P., Mroz, P., Munoz, J., Musco, I., Nesseris, S., Ozsoy, O., Pani, P., Poulin, V., Raccanelli, A., Racco, D., Raidal, M., Ranc, C., Rattenbury, N., Rhodes, J., Ricotti, M., Riotto, A., Rubin, S., Rubio, J., Ruiz-Morales, E., Sasaki, M., Schnittman, J., Shvartzvald, Y., Street, R., Takada, M., Takhistov, V., Tashiro, H., Tasinato, G., Tringas, G., Unal, C., Tada, Y., Tsapras, Y., Vaskonen, V., Veermae, H., Vidotto, F., Watson, S., Windhorst, R., Yokoyama, S., and Young, S.

Subjects
Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

The LIGO discoveries have rekindled suggestions that primordial black holes (BHs) may constitute part to all of the dark matter (DM) in the Universe. Such suggestions came from 1) the observed merger rate of the BHs, 2) their unusual masses, 3) their low/zero spins, and 4) also from the independently uncovered cosmic infrared background (CIB) fluctuations signal of high amplitude and coherence with unresolved cosmic X-ray background (CXB). Here we summarize the prospects to resolve this important issue with electromagnetic observations using the instruments and tools expected in the 2020's. These prospects appear promising to make significant, and potentially critical, advances. We demonstrate that in the next decade, new space- and ground-borne electromagnetic instruments, combined with concurrent theoretical efforts, should shed critical light on the long-considered link between primordial BHs and DM. Specifically the new data and methodologies under this program will involve: I) Probing with high precision the spatial spectrum of source-subtracted CIB with Euclid and WFIRST, and its coherence with unresolved cosmic X-ray background using eROSITA and Athena, II) Advanced searches for microlensing of Galactic stars by the intervening Galactic Halo BHs with OGLE, Gaia, LSST and WFIRST, III) Supernovae (SNe) lensing in the upcoming surveys with WFIRST, LSST and also potentially with Euclid and JWST, IV) Advanced theoretical work to understand the details of PBH accretion and evolution and their influence on cosmic microwave background (CMB) anisotropies in light of the next generation CMB experiments, V) Better new samples and theoretical understanding involving stability and properties of ultra faint dwarf galaxies, pulsar timing, and cosmological quasar lensing., Comment: Science whitepaper submitted to the Astro2020 Decadal Survey

Published
2019

3. Negative-pressure-induced helimagnetism in ferromagnetic cubic perovskites Sr$_{1-x}$Ba$_{x}$CoO$_{3}$

Author

Sakai, H., Yokoyama, S., Kuwabara, A., White, J. S., Canévet, E., Rønnow, H. M., Koretsune, T., Arita, R., Miyake, A., Tokunaga, M., Tokura, Y., and Ishiwata, S.

Subjects
Condensed Matter - Strongly Correlated Electrons, Condensed Matter - Materials Science
Abstract

Helimagnetic materials are identified as promising for novel spintronic applications. Since helical spin order is manifested as a compromise of competing magnetic exchange interactions, its emergence is limited by unique constraints imposed by the crystalline lattice and the interaction geometries, as exemplified by the multiferroic perovskite manganites with large orthorhombic distortion. Here we show that a simple cubic perovskite SrCoO$_3$ with room-temperature ferromagnetism has the potential to host helimagnetic order upon isotropic lattice expansion. Increasing the Ba content $x$ in Sr$_{1-x}$Ba$_x$CoO$_3$ continuously expands the cubic lattice, eventually suppressing the ferromagnetic order near $x$=0.4, where helimagnetic correlations are observed as incommensurate diffuse magnetic scattering by neutron diffraction measurements. The emergence of helimagnetism is semi-quantitatively reproduced by first-principles calculations, leading to the conjecture that a simple cubic lattice with strong $d$-$p$ hybridisation can exhibit a variety of novel magnetic phases originating from competing exchange interactions., Comment: 14 pages, 4 figures, To appear in Phys. Rev. Materials

Published
2018

4. First Measurements of Beam Backgrounds at SuperKEKB

Author

Lewis, P. M., Jaegle, I., Nakayama, H., Aloisio, A., Ameli, F., Barrett, M., Beaulieu, A., Bosisio, L., Branchini, P., Browder, T. E., Budano, A., Cautero, G., Cecchi, C., Chen, Y. -T., Chu, K. -N., Cinabro, D., Cristaudo, P., de Jong, S., de Sangro, R., Finocchiaro, G., Flanagan, J., Funakoshi, Y., Gabriel, M., Giordano, R., Giuressi, D., Hedges, M. T., Honkanen, N., Ikeda, H., Ishibashi, T., Kaji, H., Kanazawa, K., Kiesling, C., Koirala, S., Križan, P., La Licata, C., Lanceri, L., Liau, J. -J., Lin, F. -H., Lin, J. -C., Liptak, Z., Longo, S., Manoni, E., Marinas, C., Miyabayashi, K., Mulyani, E., Morita, A., Nakao, M., Nayak, M., Ohnishi, Y., Passeri, A., Poffenberger, P., Ritzert, M., Roney, J M., Rossi, A., Röder, T., Seddon, R. M., Seong, I. S., Shiu, J. -G., Simon, F., Soloviev, Y., Suetsugu, Y., Szalay, M., Terui, S., Tortone, G., Vahsen, S. E., van der Kolk, N., Vitale, L., Wang, M. Z., Windel, H., and Yokoyama, S.

Subjects
Physics - Instrumentation and Detectors, High Energy Physics - Experiment, Physics - Accelerator Physics
Abstract

The high design luminosity of the SuperKEKB electron-positron collider is expected to result in challenging levels of beam-induced backgrounds in the interaction region. Properly simulating and mitigating these backgrounds is critical to the success of the Belle~II experiment. We report on measurements performed with a suite of dedicated beam background detectors, collectively known as BEAST II, during the so-called Phase 1 commissioning run of SuperKEKB in 2016, which involved operation of both the high energy ring (HER) of 7 GeV electrons as well as the low energy ring (LER) of 4 GeV positrons. We describe the BEAST II detector systems, the simulation of beam backgrounds, and the measurements performed. The measurements include standard ones of dose rates versus accelerator conditions, and more novel investigations, such as bunch-by-bunch measurements of injection backgrounds and measurements sensitive to the energy spectrum and angular distribution of fast neutrons. We observe beam-gas, Touschek, beam-dust, and injection backgrounds. We do not observe significant synchrotron radiation, as expected. Measured LER beam-gas backgrounds and Touschek backgrounds in both rings are slightly elevated, on average three times larger than the levels predicted by simulation. HER beam-gas backgrounds are on on average two orders of magnitude larger than predicted. Systematic uncertainties and channel-to-channel variations are large, so that these excesses constitute only 1-2 sigma level effects. Neutron background rates are higher than predicted and should be studied further. We will measure the remaining beam background processes, due to colliding beams, in the imminent commissioning Phase 2. These backgrounds are expected to be the most critical for Belle II, to the point of necessitating replacement of detector components during the Phase 3 (full-luminosity) operation of SuperKEB., Comment: 101 pages, 127 figures

Published
2018
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8. Enduring effects of a five-week behavioral activation program for subthreshold depression among late adolescents: an exploratory randomized controlled trial

Author

Takagaki K, Okamoto Y, Jinnin R, Mori A, Nishiyama Y, Yamamura T, Yokoyama S, Shiota S, Miyake Y, Ogata A, Kunisato Y, Shimoda H, Kawakami N, Furukawa TA, and Yamawaki S

Subjects
Behavioral activation, First-year university students, Randomized controlled trial, Subthreshold depression, Neurosciences. Biological psychiatry. Neuropsychiatry, RC321-571, Neurology. Diseases of the nervous system, RC346-429
Abstract

Koki Takagaki,1 Yasumasa Okamoto,2 Ran Jinnin,2 Asako Mori,2 Yoshiko Nishiyama,3 Takanao Yamamura,4 Satoshi Yokoyama,2 Syouichi Shiota,5,6 Yuri Okamoto,1 Yoshie Miyake,1 Akiko Ogata,7 Yoshihiko Kunisato,8 Haruki Shimoda,9 Norito Kawakami,10 Toshi A Furukawa,11 Shigeto Yamawaki2 1Health Service Center, Hiroshima, Japan; 2Department of Psychiatry and Neurosciences, Hiroshima University, Hiroshima, Japan; 3Haruma City Office, Haruma, Japan; 4Kanazawa University Hospital Neuropsychiatry, Kanazawa, Japan; 5Japan Society for the Promotion of Science, Tokyo, Japan; 6Department of Cognitive Psychology in Education, Graduate School of Education, Kyoto University, Kyoto, Japan; 7Department of Psychology, Hiroshima University, Hiroshima, Japan; 8Department of Psychology, School of Human Sciences, Senshu University, Kawasaki, Japan; 9Department of Hygiene and Preventive Medicine, School of Medicine, Iwate Medical University, Morioka, Japan; 10Department of Psychiatry of Mental Health, The University of Tokyo, Tokyo, Japan; 11Department of Health Promotion and Human Behavior and of Clinical Epidemiology, Kyoto University Graduate School of Medicine/School of Public health, Kyoto, Japan Background: No significant effect of psychological treatment has been reported from meta-analysis of subthreshold depression patients and control subjects at 1-year follow-up. However, behavioral activation is a simpler and more cost-effective treatment than cognitive behavioral therapy. The primary purpose of this study was to assess by comparison to an assessment-only control group whether the effects of behavioral activation program for depressive symptoms can persist up to 1-year follow-up without the use of antidepressants or other psychotherapy.Patients and methods: Late adolescent students were the population targeted in this study. Participants were allocated randomly to an intervention group (n=62) or a control group (n=56). Treatment consisted of five-weekly 60-minute sessions. Participants underwent a structured interview and completed self-report scales at 1 year post-assessment.Results: Late adolescent students receiving treatment had significantly lower mean Beck Depression Inventory, second edition scores at 1-year follow-up than control group students. The effect size (Hedges’ g) for between-group differences at 1-year follow-up was -0.41.Conclusion: Our behavioral activation program is simple and short. Nevertheless, the results obtained at 1-year follow-up of the control group and late adolescent students receiving treatment indicated a significant difference in their Beck Depression Inventory, second edition scores. Our 5-week behavioral activation program based on behavioral characteristics for subthreshold depression might be promising for subthreshold depression. The sample examined for this study imposed some study limitations. Keywords: behavioral activation, first-year university students, randomized controlled trial, subthreshold depression

Published
2018

9. Effects of behavioral activation program without psychotropic medication treatment for depression in late adolescence: case report

Author

Takagaki K, Okamoto Y, Jinnin R, Yokoyama S, Yoshino A, Kagawa F, Miyake Y, and Yamawaki S

Subjects
avoidant behavior, behavioral activation without psychotropic medication, major depressive symptoms, rumination, Neurosciences. Biological psychiatry. Neuropsychiatry, RC321-571, Neurology. Diseases of the nervous system, RC346-429
Abstract

Koki Takagaki,1 Yasumasa Okamoto,1 Ran Jinnin,1 Satoshi Yokoyama,1 Atsuo Yoshino,1 Fumi Kagawa,1 Yuri Okamoto,2 Yoshie Miyake,2 Shigeto Yamawaki1 1Department of Psychiatry and Neurosciences, Hiroshima University, Hiroshima, Japan; 2Health Service Center, Hiroshima University, Hiroshima, Japan Background: A Japanese study revealed that 20.7% of first-year undergraduate students had a major depressive episode during the previous 12 months: first-year undergraduate students with depression need early support. Reportedly, antidepressant medication use during adolescence is associated with modestly increased risk of suicidality. This case study of a late-adolescent woman with depression illustrates the effects of behavioral activation without psychotropic medication.Case presentation: A first-year undergraduate student was diagnosed as having major depressive disorder. From earlier studies, we developed a behavioral activation program for late-adolescent people with major depressive disorder. Behavioral activation administered in 10 weekly 60-minute sessions decreased depressive symptoms, avoidant behaviors, and rumination. Moreover, the Beck Depression Inventory, second version score was 1 at 1-year follow-up.Conclusion: Results of this case study show that behavioral activation is effective without psychotropic medication. Future studies of large samples must be conducted to assess the effectiveness of behavioral activation without psychotropic medication for depression in late adolescence. Keywords: avoidant behavior, behavioral activation without psychotropic medication, major depressive symptoms, rumination

Published
2018

10. Clinical outcomes of endoscope-assisted vitrectomy for treatment of rhegmatogenous retinal detachment

Author

Yokoyama S, Kojima T, Mori T, Matsuda T, Sato H, Yoshida N, Kaga T, Smith RT, and Ichikawa K

Subjects
Endoscope-assisted vitrectomy, endoscopic vitrectomy, ophthalmic endoscope, retinal detachment, rhegmatogenous retinal detachment, Ophthalmology, RE1-994
Abstract

Sho Yokoyama,1 Takashi Kojima,2 Toshio Mori,3 Taisuke Matsuda,1 Hiroyuki Sato,3 Norihiko Yoshida,4 Tatsushi Kaga,1 R Theodore Smith,5 Kazuo Ichikawa6 1Department of Ophthalmology, Japan Community Healthcare Organization Chukyo Hospital, Nagoya, Japan; 2Department of Ophthalmology, Keio University School of Medicine, Tokyo, Japan; 3Department of Ophthalmology, Iida Municipal Hospital, Iida, Japan; 4Department of Ophthalmology, Japanese Red Cross Gifu Hospital, Gifu, Japan; 5Department of Ophthalmology, New York University School of Medicine, New York, NY, USA; 6Chukyo Eye Clinic, Nagoya, Japan Summary: We evaluated the clinical outcomes for ophthalmic endoscope-assisted vitrectomy in consecutive patients with uncomplicated rhegmatogenous retinal detachment (RRD). The primary success rate was 98.4% (125/127) without performing a posterior drainage retinotomy or using perfluorocarbon liquids (PFCL) for subretinal fluid drainage.Purpose: To investigate the clinical outcomes of endoscope-assisted vitrectomy in patients with uncomplicated RRD.Methods: We examined 127 eyes from consecutive patients who underwent repair of RRD by 23- or 25-gauge endoscope-assisted vitrectomy, with a minimum follow-up of 3 months. Eyes with the following criteria were excluded: Giant retinal tears, grade C proliferative vitreoretinopathy, dense vitreous hemorrhage, retinal detachment secondary to other ocular diseases, and prior retinal or vitreous surgery. All cases underwent subretinal fluid drainage, endolaser photocoagulation and fundus inspection were performed under ophthalmic endoscopic observation. Success rate, visual acuity, surgery time and complications were evaluated.Results: Primary and final success rate was 98.4% (125/127) and 100% (127/127), respectively, Surgery time was 59.6±26.3 minutes. The best-corrected visual acuity significantly improved from 20/100 to 20/20 (P

Published
2017

11. Exploring Heterogeneity in Happiness: Evidence from a Japanese Longitudinal Survey

Author

Okada, A, Shigemasu, K, Yoshino, R, Yokoyama, S, Pennoni, F, Nakai, M, Okada, A, Shigemasu, K, Yoshino, R, Yokoyama, S, Pennoni, F, and Nakai, M

Abstract

The present research explores the heterogeneity in trajectories of subjective well-being of Japanese citizens using longitudinal data collected with the Preference Parameters Study from 2003 to 2018. The analysis is carried out through the hidden Markov model that assumes a latent process underlying the individual perception of happiness observed through a categorical response variable. The first-order Markov chain is parameterized in terms of initial and transition probabilities depending on time-constant and time-varying socioeconomic and demographic variables. Maximum likelihood estimation of model parameters accounts for longitudinal sampling weights and missing responses under the Missing-At-Random assumption. Through this model-based clustering approach, we discover three clusters of individuals showing different dynamics across the life course, each of which represents, namely “not so happy”, “moderately happy”, and “very happy” individuals. We find that males tend to be less happy than females, and a U-shaped association between happiness and age is not detected. Each state has a substantial persistence over time, meaning that initial happiness perceptions play an important role in the life course inequalities of subjective well-being.

Published
2023

12. Examining Cross-Cultural Value Questionnaires with Quantitative Methods: Reliability and scalar equivalence of the measurement instruments of human values in Germany and Japan

Author

Okada, Akinori, Shigemasu, Kazuo, Yoshino, Ryozo, Yokoyama, Satoru, Okada, A ( Akinori ), Shigemasu, K ( Kazuo ), Yoshino, R ( Ryozo ), Yokoyama, S ( Satoru ), Jagodzinski, Wolfgang, Manabe, Kazufumi, Dülmer, Hermann, Hommerich, Carola, Davidov, Eldad; https://orcid.org/0000-0002-3396-969X, Okada, Akinori, Shigemasu, Kazuo, Yoshino, Ryozo, Yokoyama, Satoru, Okada, A ( Akinori ), Shigemasu, K ( Kazuo ), Yoshino, R ( Ryozo ), Yokoyama, S ( Satoru ), Jagodzinski, Wolfgang, Manabe, Kazufumi, Dülmer, Hermann, Hommerich, Carola, and Davidov, Eldad; https://orcid.org/0000-0002-3396-969X

Abstract

Good measurement instruments have to meet certain necessary conditions, especially if they are to be used in cross-cultural research. In this study, we examine whether the German and Japanese translations of Shalom Schwartz's PVQ-57 fulfill two of these conditions. The survey measures 19 human values by 57 indicators. First, we examine whether these human values are reliably measured in a student survey which was carried out in autumn/winter 2018 at German and Japanese universities. Second, we investigate whether the instruments allow the comparison of latent value means across the German and Japanese student samples. Such a comparison is meaningful only if scalar equivalence, a high form of measurement equivalence, is reached. Results suggest that at least partial scalar invariance can be established across the samples. We discuss the findings in the broader perspective of value research and outline topics for further investigation.

Published
2023

13. Two-dimensional echocardiographic scoring system of the left ventricular filling pressure and clinical outcomes in heart failure with preserved ejection fraction

Author

Murayama, M, primary, Iwano, H, additional, Obokata, M, additional, Harada, T, additional, Omote, K, additional, Tsujinaga, S, additional, Chiba, Y, additional, Ishizaka, S, additional, Motoi, K, additional, Nakabachi, M, additional, Nishino, H, additional, Yokoyama, S, additional, Nishida, M, additional, Kurabayashi, M, additional, and Anzai, T, additional

Published
2022
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19. First measurements of beam backgrounds at SuperKEKB

Author

Lewis, P. M., Jaegle, I., Budano, A., Cautero, G., Cecchi, C., Chen, Y.-T., Chu, K.-N., Cinabro, D., Cristaudo, P., de Jong, S., de Sangro, R., Finocchiaro, G., Nakayama, H., Flanagan, J., Funakoshi, Y., Gabriel, M., Giordano, R., Giuressi, D., Hedges, M. T., Honkanen, N., Ikeda, H., Ishibashi, T., Kaji, H., Aloisio, A., Kanazawa, K., Kiesling, C., Koirala, S., Križan, P., La Licata, C., Lanceri, L., Liau, J.-J., Lin, F.-H., Lin, J.-C., Liptak, Z., Ameli, F., Longo, S., Manoni, E., Marinas, C., Miyabayashi, K., Mulyani, E., Morita, A., Nakao, M., Nayak, M., Ohnishi, Y., Passeri, A., Barrett, M., Poffenberger, P., Ritzert, M., Roney, J. M., Rossi, A., Röder, T., Seddon, R. M., Seong, I. S., Shiu, J.-G., Simon, F., Soloviev, Y., Beaulieu, A., Suetsugu, Y., Szalay, M., Terui, S., Tortone, G., Vahsen, S. E., van der Kolk, N., Vitale, L., Wang, M.-Z., Windel, H., Yokoyama, S., Bosisio, L., Belle II Collaboration, Branchini, P., Browder, T. E., Lewis, P. M., Jaegle, I., Nakayama, H., Aloisio, A., Ameli, F., Barrett, M., Beaulieu, A., Bosisio, L., Branchini, P., Browder, T. E., Budano, A., Cautero, G., Cecchi, C., Chen, Y. -T., Chu, K. -N., Cinabro, D., Cristaudo, P., de Jong, S., de Sangro, R., Finocchiaro, G., Flanagan, J., Funakoshi, Y., Gabriel, M., Giordano, R., Giuressi, D., Hedges, M. T., Honkanen, N., Ikeda, H., Ishibashi, T., Kaji, H., Kanazawa, K., Kiesling, C., Koirala, S., Križan, P., La Licata, C., Lanceri, L., Liau, J. -J., Lin, F. -H., Lin, J. -C., Liptak, Z., Longo, S., Manoni, E., Marinas, C., Miyabayashi, K., Mulyani, E., Morita, A., Nakao, M., Nayak, M., Ohnishi, Y., Passeri, A., Poffenberger, P., Ritzert, M., Roney, J. M., Rossi, A., Röder, T., Seddon, R. M., Seong, I. S., Shiu, J. -G., Simon, F., Soloviev, Y., Suetsugu, Y., Szalay, M., Terui, S., Tortone, G., Vahsen, S. E., van der Kolk, N., Vitale, L., Wang, M. -Z., Windel, H., and Yokoyama, S.

Subjects
Accelerator Physics (physics.acc-ph), Nuclear and High Energy Physics, Physics - Instrumentation and Detectors, FOS: Physical sciences, Synchrotron radiation, Accelerator, BELLE, Electron, 01 natural sciences, 7. Clean energy, Beam–gas, law.invention, High Energy Physics - Experiment, Beam background, Nuclear physics, High Energy Physics - Experiment (hep-ex), Beam–ga, KEK-B, law, 0103 physical sciences, Electron–positron collider, ddc:530, Neutron, Detectors and Experimental Techniques, angular distribution [n], numerical calculations, 010306 general physics, Collider, Touschek, Instrumentation, Nuclear and High Energy Physic, Physics, Luminosity (scattering theory), synchrotron radiation, 010308 nuclear & particles physics, energy spectrum [n], Detector, Instrumentation and Detectors (physics.ins-det), Neutron temperature, induced [background], Physics::Accelerator Physics, Physics - Accelerator Physics, injection [beam], Infrastructure for advanced calorimeters [14], Beam (structure)
Abstract

The high design luminosity of the SuperKEKB electron-positron collider is expected to result in challenging levels of beam-induced backgrounds in the interaction region. Properly simulating and mitigating these backgrounds is critical to the success of the Belle~II experiment. We report on measurements performed with a suite of dedicated beam background detectors, collectively known as BEAST II, during the so-called Phase 1 commissioning run of SuperKEKB in 2016, which involved operation of both the high energy ring (HER) of 7 GeV electrons as well as the low energy ring (LER) of 4 GeV positrons. We describe the BEAST II detector systems, the simulation of beam backgrounds, and the measurements performed. The measurements include standard ones of dose rates versus accelerator conditions, and more novel investigations, such as bunch-by-bunch measurements of injection backgrounds and measurements sensitive to the energy spectrum and angular distribution of fast neutrons. We observe beam-gas, Touschek, beam-dust, and injection backgrounds. We do not observe significant synchrotron radiation, as expected. Measured LER beam-gas backgrounds and Touschek backgrounds in both rings are slightly elevated, on average three times larger than the levels predicted by simulation. HER beam-gas backgrounds are on on average two orders of magnitude larger than predicted. Systematic uncertainties and channel-to-channel variations are large, so that these excesses constitute only 1-2 sigma level effects. Neutron background rates are higher than predicted and should be studied further. We will measure the remaining beam background processes, due to colliding beams, in the imminent commissioning Phase 2. These backgrounds are expected to be the most critical for Belle II, to the point of necessitating replacement of detector components during the Phase 3 (full-luminosity) operation of SuperKEB., 101 pages, 127 figures

Published
2019
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22. Feasibility study of a coherent feedback squeezer

Author

Yokoyama, S, Peace, D, Asavanant, W, Tajiri, T, Haylock, B, Ghadimi, M, Lobino, M, Huntington, EH, Yonezawa, H, Yokoyama, S, Peace, D, Asavanant, W, Tajiri, T, Haylock, B, Ghadimi, M, Lobino, M, Huntington, EH, and Yonezawa, H

Abstract

© 2020 American Physical Society. We investigate a coherent feedback squeezer that uses quantum coherent feedback (measurement-free) control. Our squeezer is simple, easy to implement, robust to the gain fluctuation, and broadband compared to the existing squeezers because of the negative coherent feedback configuration. We conduct a feasibility study that looks at the stability conditions for a feedback system to optimize the designs of real optical devices. The feasibility study gives fabrication tolerance necessary for designing and realizing the actual device. Our formalism for the stability analysis is not limited to optical systems but can be applied to the other bosonic systems.

Published
2020

23. Exploring hierarchical concepts: theoretical and application comparisons

Author

Imaizumi, T, Nakayama, A, Yokoyama, S, Cavicchia, C, Vichi, M, Zaccaria, G, Imaizumi, T, Nakayama, A, Yokoyama, S, Cavicchia, C, Vichi, M, and Zaccaria, G

Abstract

Phenomena are usually multidimensional and their complexity cannot be directly explored via observable variables. For this reason, a hierarchical structure of nested latent concepts representing different levels of abstraction of the phenomenon under study may be considered. In this paper, we provide a comparison between a procedure based on hierarchical clustering methods and a novelty model recently proposed, called Ultrametric Correlation Matrix (UCM) model. The latter aims at reconstructing the data correlation matrix via an ultrametric correlation matrix and supplies a parsimonious representation of multidimensional phenomena through a partition of the observable variables defining a reduced number of latent concepts. Moreover, the UCM model highlights two main features related to concepts: the correlation among concepts and the internal consistency of a concept. The performances of the UCM model and the procedure based on hierarchical clustering methods are illustrated by an application to the Holzinger data set which represents a real demonstration of a hierarchical factorial structure. The evaluation of the different methodological approaches—the UCM model and the procedure based on hierarchical clustering methods—is provided in terms of classification of variables and goodness of fit, other than of their suitability to analyse bottom-up latent structures of variables.

Published
2020

24. JQ1 affects BRD2-dependent and independent transcription regulation without disrupting H4-hyperacetylated chromatin states

Author

Handoko, L., Kaczkowski, B., Hon, C. C., Lizio, M., Wakamori, M., Matsuda, T., Ito, T., Jeyamohan, P., Sato, Y., Sakamoto, K., Yokoyama, S., Kimura, Hiroshi, Minoda, A., and Umehara, T.

Subjects
0301 basic medicine, Models, Molecular, Cage, Cancer Research, Lung Neoplasms, Histones, Mice, Lung Neoplasms/drug therapy/*genetics/metabolism, Carcinoma, Non-Small-Cell Lung, Transcriptional regulation, Histone code, Promoter Regions, Genetic, Azepines/*pharmacology, Triazoles/*pharmacology, Brd2, biology, Chemistry, Acetylation, Azepines, Chromatin, Cell biology, Jq1, Gene Expression Regulation, Neoplastic, Histone, Protein-Serine-Threonine Kinases/*metabolism, Transcription Initiation Site, Proto-Oncogene Proteins c-myc/genetics, Protein Serine-Threonine Kinases, Proto-Oncogene Proteins c-myc, Histone H4, Chromatin/metabolism, 03 medical and health sciences, Cell Line, Tumor, Animals, Humans, Enhancer, Molecular Biology, Transcription factor, Promoter Regions, Genetic/drug effects, Transcription Initiation Site/drug effects, Carcinoma, Non-Small-Cell Lung/drug therapy/*genetics/metabolism, Promoter, Triazoles, Acetylation/drug effects, Bromodomain, 030104 developmental biology, Histones/*chemistry/metabolism, Gene Expression Regulation, Neoplastic/drug effects, Bet, biology.protein, Cancer research, H4 hyperacetylation, Transcription Factors
Abstract

The bromodomain and extra-terminal domain (BET) proteins are promising drug targets for cancer and immune diseases. However, BET inhibition effects have been studied more in the context of bromodomain-containing protein 4 (BRD4) than BRD2, and the BET protein association to histone H4-hyperacetylated chromatin is not understood at the genome-wide level. Here, we report transcription start site (TSS)-resolution integrative analyses of ChIP-seq and transcriptome profiles in human non-small cell lung cancer (NSCLC) cell line H23. We show that di-acetylation at K5 and K8 of histone H4 (H4K5acK8ac) co-localizes with H3K27ac and BRD2 in the majority of active enhancers and promoters, where BRD2 has a stronger association with H4K5acK8ac than H3K27ac. Although BET inhibition by JQ1 led to complete reduction of BRD2 binding to chromatin, only local changes of H4K5acK8ac levels were observed, suggesting that recruitment of BRD2 does not influence global histone H4 hyperacetylation levels. This finding supports a model in which recruitment of BET proteins via histone H4 hyperacetylation is predominant over hyperacetylation of histone H4 by BET protein-associated acetyltransferases. In addition, we found that a remarkable number of BRD2-bound genes, including MYC and its downstream target genes, were transcriptionally upregulated upon JQ1 treatment. Using BRD2-enriched sites and transcriptional activity analysis, we identified candidate transcription factors potentially involved in the JQ1 response in BRD2-dependent and -independent manner.

Published
2018

27. Simple echocardiographic scoring system to estimate left ventricular filling pressure based on visual assessment of time sequence of mitral and tricuspid valve opening

Author

Murayama, M, primary, Iwano, H, additional, Tsujinaga, S, additional, Nishino, H, additional, Yokoyama, S, additional, Nakabachi, M, additional, Sarashina, M, additional, Ishizaka, S, additional, Chiba, Y, additional, Okada, K, additional, Kaga, S, additional, Nishida, M, additional, Kamiya, K, additional, Nagai, T, additional, and Anzai, T, additional

Published
2020
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29. Derivation of I(sub c) degradation rate for Nb3Sn coils through the react & wind technique

Author

Kubo, Y., Yokoyama, S., Ozawa, T., Komatsu, S., and Hiramoto, K.

Subjects
Electrical wire -- Mechanical properties, Electric coils -- Mechanical properties, Business, Electronics, Electronics and electrical industries
Abstract

A study is conducted to estimate critical current, I(sub c), degradation when bending and tensile are applied to Nb3Sn wires through react & wind technique, by analyzing the degradation and considering the shift of the neutral axis when the wire is bent. The results indicate that the neutral axis shifts 72 mu m from the center of he wire toward the inside.

Published
2004

30. Quench characteristics of fault current limiting element with YBCO thin film

Author

Shimohata, K., Yokoyama, S., Inaguchi, T., Nakamura, S., and Yasuda, Kenji

Subjects
Superconductive devices -- Research, Superconductors -- Research, Thin films -- Research, Dielectric films -- Research, Business, Electronics, Electronics and electrical industries
Abstract

Experiments aimed at development of a resistive fault current limiting element with YBCO thin film are described and discussed.

Published
2003

31. Poster session: Aortic stenosis

Author

Yamada, S, Okada, K, Iwano, H, Nishino, H, Nakabachi, M, Yokoyama, S, Kaga, S, Mikami, T, and Tsutsui, H

Published
2012

37. Distribution arrester failures caused by lightning current flowing from customer's structure to distribution lines

Author

Nakada, K., Wakai, T., Taniguchi, H., Kawabata, T., Yokoyama, S., Yokota, T., and Asakawa, A.

Subjects
Lightning-arresters -- Research, Surge suppressors -- Research, Business, Computers, Electronics, Electronics and electrical industries
Abstract

Distribution arrester failures have been thought to be caused by direct or nearby lightning strokes. We have, however, found that distribution arrester failure is caused by part of the lightning current which flows into distribution lines when the customer's structure is struck by lightning. We call this current 'lightning backflow current'. In order to clarify the influence of lightning backflow current on arrester failure, we have conducted experimental and analytical studies and observed the distribution outages. The main results are as follows. (1) The calculated failure probability of an arrester caused by lightning backflow current in winter is almost equal to that caused by a direct lightning stroke to distribution lines. (2) According to the investigation of lightning-caused failures, about half of the arrester failures are due to lightning backflow current. (3) Lightning backflow current should be considered as one of the main causes of distribution arrester failures. Keywords: Lightning; Distribution Line; Surge Arrester; Arrester Failure.

Published
1999

38. Electromagnetic probes of primordial black holes as dark matter

Author

Kashlinsky, A., Ali-Haimoud, Y., Clesse, S., Garcia-Bellido, J., Wyrzykowski, L., Achucarro, A., Amendola, L., Annis, J., Arbey, A., Arendt, R. G., Atriobarandela, F., Bellomo, N., Belotsky, K., Bernal, J-L, Bird, S., Bozza, V., Byrnes, C., Calchi Novati, S., Calore, F., Carr, B. J., Chluba, J., Cholis, I., Cieplak, A., Cole, P., Dalianis, I., Davis, A-C, Davis, T., Luca, V., Dvorkin, I., Emparan, R., Ezquiaga, J-M, Fleury, P., Franciolini, G., Gaggero, D., Georg, J., Germani, C., Giudice, G-F, Goobar, A., Hasinger, G., Hector, A., Hundertmark, M., Hutsi, G., Jansen, R., Kamionkowski, M., Kawasaki, M., Kazanas, D., Kehagias, A., Khlopov, M., Knebe, A., Kohri, K., Koushiappas, S., Kovetz, E., Kuhnel, F., Macgibbon, J., Marzola, L., Mediavilla, E., Meszaros, P., Mroz, P., Munoz, J., Musco, I., Nesseris, S., Ozsoy, O., Pani, P., Poulin, V., Raccanelli, A., Racco, D., Raidal, M., Ranc, C., Rattenbury, N., Rhodes, J., Ricotti, M., Riotto, A., Rubin, S., Rubio, J., Ruiz-Morales, E., Sasaki, M., Schnittman, J., Shvartzvald, Y., Street, R., Takada, M., Takhistov, V., Tashiro, H., Tasinato, G., Tringas, G., Caner Unal, Tada, Y., Tsapras, Y., Vaskonen, V., Veermae, H., Vidotto, F., Watson, S., Windhorst, R., Yokoyama, S., Young, S., Université Claude Bernard Lyon 1 (UCBL), Université de Lyon, Centre National de la Recherche Scientifique (CNRS), Laboratoire Univers et Particules de Montpellier (LUPM), Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique Nucléaire de Lyon (IPNL), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), and Université de Montpellier (UM)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Astrophysics and Astronomy, Cosmology and Nongalactic Astrophysics (astro-ph.CO), lens, Astrophysics::High Energy Astrophysical Phenomena, spin: 0, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, dark matter: density, galaxy: halo, star, accretion, supernova, quasar, LIGO, Astrophysics::Galaxy Astrophysics, pulsar, fluctuation, Astrophysics::Instrumentation and Methods for Astrophysics, stability, coherence, electromagnetic, X-ray: background, infrared, astro-ph.CO, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], black hole: primordial, Astrophysics - Cosmology and Nongalactic Astrophysics, cosmic background radiation: anisotropy
Abstract

The LIGO discoveries have rekindled suggestions that primordial black holes (BHs) may constitute part to all of the dark matter (DM) in the Universe. Such suggestions came from 1) the observed merger rate of the BHs, 2) their unusual masses, 3) their low/zero spins, and 4) also from the independently uncovered cosmic infrared background (CIB) fluctuations signal of high amplitude and coherence with unresolved cosmic X-ray background (CXB). Here we summarize the prospects to resolve this important issue with electromagnetic observations using the instruments and tools expected in the 2020's. These prospects appear promising to make significant, and potentially critical, advances. We demonstrate that in the next decade, new space- and ground-borne electromagnetic instruments, combined with concurrent theoretical efforts, should shed critical light on the long-considered link between primordial BHs and DM. Specifically the new data and methodologies under this program will involve: I) Probing with high precision the spatial spectrum of source-subtracted CIB with Euclid and WFIRST, and its coherence with unresolved cosmic X-ray background using eROSITA and Athena, II) Advanced searches for microlensing of Galactic stars by the intervening Galactic Halo BHs with OGLE, Gaia, LSST and WFIRST, III) Supernovae (SNe) lensing in the upcoming surveys with WFIRST, LSST and also potentially with Euclid and JWST, IV) Advanced theoretical work to understand the details of PBH accretion and evolution and their influence on cosmic microwave background (CMB) anisotropies in light of the next generation CMB experiments, V) Better new samples and theoretical understanding involving stability and properties of ultra faint dwarf galaxies, pulsar timing, and cosmological quasar lensing., Comment: Science whitepaper submitted to the Astro2020 Decadal Survey

Published
2019

42. Energy absorption of surge arresters on power distribution lines due to direct lightning strokes: effects of an overhead ground wire and installation position of surge arresters

Author

Nakada, K., Yokota, T., Yokoyama, S., Asakawa, A., Nakamura, M., Taniguchi, H., and Hashimoto, A.

Subjects
Surge suppressors -- Analysis, Electric power distribution -- Analysis, Lightning-arresters -- Analysis, Business, Computers, Electronics, Electronics and electrical industries
Abstract

We describe the characteristics of energy absorption of surge arresters on power distribution lines due to direct lightning strokes. Using the EMTP, the effect of an overhead ground wire and the influence of the installation position of a surge attester on the energy absorption are investigated quantitatively. The analysis shows that: (1) an overhead ground wire is more effective to prevent damage to surge arresters than increasing the withstand capabilities of surge arresters by a factor of two, (2) the energy absorption without an overhead ground wire is about 3[similar to]5 times larger than that with one, and (3) in the case of direct lightning strokes to an overhead ground wire, the energy absorption of surge arresters installed at the termination of a line is approximately 2.3 times larger at maximum than that of arresters installed in the midst of a line. KEYWORDS - Lightning; Power Distribution Line; Surge Arrester; Overhead Ground Wire.

Published
1997

43. Two types of lightning discharges to a high stack on the coast of the Sea of Japan in winter

Author

Asakawa, A., Miyake, K., Yokoyama, S., Shindo, T., Yokota, T., and Sakai, T.

Subjects
Lightning -- Research, Electric discharges -- Research, Business, Computers, Electronics, Electronics and electrical industries
Abstract

To clarify the characteristics of lightning on the coast of the Sea of Japan in winter season, the current waveform and the progression of lightning discharge to a high stack were observed. Observation results from 1989 to 1994 show that; (1) There are two types of lightning discharges; One with large currents and strong luminosity in the lightning path, and the other with small currents of long duration and weak luminosity of lightning path. (2) The parameters of lightning currents of the two types of discharges are quite different. (3) There is a quantitative correlation between the change of luminosity in a lightning path an d the lightning current waveform. KEYWORD - Lightning; Lightning discharge; Lightning current; Lightning parameter

Published
1997

45. Cryogen free conduction cooled NbTi superconducting magnet for a X-band klystron

Author

Yokoyama, S., Minato, T., Imai, Y., Inaguchi, T., Kim, T.H., Umemura, T., Ogitsu, T., and Mizuno, H.

Subjects
Superconducting magnets -- Design and construction, Solenoids -- Design and construction, Klystrons -- Equipment and supplies, Business, Electronics, Electronics and electrical industries
Abstract

A cryogen free conduction cooled NbTi superconducting magnet for a X-band klystron was designed,fabricated, and tested successfully. The magnet has a room temperature bore of 190 mm. The rated field is 0.7 T. In order to meet the requested magnetic field distribution, the NbTi coil is separated to three parts and a return yoke is set. The coil is cooled by a two-stage Gifford-McMahon cycle refrigerator. The refrigeration capacity is 1.1 W at 6 K and 30 W at 40 K for each stage. Current leads are made of 2223 Bi-based oxide superconductor. The coil was cooled down to superconducting state from room temperature in 85 hours. The ultimate temperature of the coil was below 4K, and the coil was energized without quench to 18.5 A which was 105% of rated current. The power consumption of 6 kW is 1/8 of the normal conducting magnet. The thermal leak of 0.2 W into the coil was measured, which was the same value of the design.

Published
1996

47. A conceptual design of a superconducting magnet for MAGLEV using a Bi-based high-Tc tape

Author

Yokoyama, S., Shimohata, K., Inaguchi, T., Takeuchi, T., Kim, T., Nakamura, S., Miyashita, S., and Uchikawa, F.

Subjects
Superconducting magnets -- Design and construction, High temperature superconductors -- Usage, Magnetic levitation vehicles -- Research, Magnetic suspension -- Research, Business, Electronics, Electronics and electrical industries
Abstract

The design of a superconducting magnet for a magnetic levitation vehicle is considered. Specifically, the configuration of the conductor, coil, current lead, persistent current switch, cryostat and cooling system are discussed along with factors that contribute to ac loss and stability. Subsequently, a cryogen-free magnet wound from high-temperature superconducting tape and conduction-cooled by two Gifford-McMahon refrigerators is introduced.

Published
1995

48. Superconducting bending magnets for compact synchrotron radiation source

Author

Yamamoto, S., Kawaguchi, T., Matsuda, T., Takeuchi, T., Kodera, I., Amano, T., Morita, M., Yokoyama, S., Shimohata, K., Nakamura, S., Yamada, Y., and Iwamoto, M.

Subjects
Superconducting magnets -- Research, Synchrotron radiation sources -- Research, Business, Electronics, Electronics and electrical industries
Abstract

The design and performance of a superconducting magnet for an 800-MeV synchrotron radiation source are presented. The 4.5-T bending magnet operates on persistent current mode, has a low consumption ratio of liquid helium and contains coils with a dipole, quadrupole and sextupole geometry. Tests on its persistent current switches and superconducting joints confirm its successful operation.

Published
1993

49. Study of joint resistance in [Nb.sub.3]Al-NbTi superconducting joint for high field NMR

Author

Fukuzaki, T., Maeda, H., Matsumoto, S., Yokoyama, S., and Kiyoshi, T.

Subjects
Niobium -- Electric properties, Nuclear magnetic resonance -- Usage, Superconductors -- Electric properties, Business, Electronics, Electronics and electrical industries
Abstract

The article studies an NbTi coil and an [Nb.sub.3]Al-NbTi superconducting joint operating in the persistent current mode. Results suggest that a sufficiently good joint resistance of 1.27 X [10.sup.-12] was obtained for high field NMR.

Published
2007

50. The 2018 revision of the standard IEC 61400-24 : lightning protection of wind turbines

Author

Méndez, Y., Abild Jensen, H., Sørensen, T. S., Hermoso, B., Plumer, J. A., Groenhagen, J., Hansen, A. N., Saounde, J. G., Pedersen, B. E., Birkl, J., McNiff, B., Bertelsen, K., Rittinghaus, C., Yamamoto, K., Thiel, E., Rodríguez Valentín, L., Hansen, L. B., Ono, S., Kimura, M., Songye, Caie, M., Christiansen, T. L., Hrescak, M., March, V., Woebbeking, M., Matsushita, T., Montanya, J., Barton, W., Siew, W. H., Wang, X., Baker, R., Yasuda, Y., Madsen, S. F., Zhou, Q., Funabashi, S., Zhou, X., Yokoyama, S., and Zhuang, Y.

Subjects
TK
Abstract

The first edition of the standard IEC 61400-24, Wind Generator Systems – Part 24 Lightning Protection, was issued in June 2010, and the scope was to reflect the experiences and technical understanding of lightning protection of wind turbines by manufacturers, certification organizations, research institutes and universities. It presented background statistical information on lightning damage to wind turbines, and it provided guidance on lightning protection best practices. Since then, the wind power industry has further developed towards even larger onshore and offshore wind turbines and into a mature industry. This is the background for the current draft of the 2018 revision of the IEC 61400-24, which transforms the 2010 edition into an evolution of the previous issued standard based on improved technical experience and expertise.

Published
2018

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