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5,522 results on '"Yokoyama, S."'

3. 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

4. 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

5. 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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10. Application of a novel echocardiographic scoring system to estimate left ventricular filling pressure in aortic stenosis

Author

Aoyagi, H, primary, Iwano, H, additional, Murayama, M, additional, Yokoyama, S, additional, Nishino, H, additional, Nakabachi, M, additional, Nakamura, K, additional, Tamaki, Y, additional, Motoi, K, additional, Kobayashi, Y, additional, Ishizaka, S, additional, Kaga, S, additional, Kamiya, K, additional, Nagai, T, additional, and Anzai, T, additional

Published
2023
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11. Control of emission diffraction angles and laser threshold in mixed-order sampled distributed feedback laser with organic gain media.

Author

Park, H., Alasvand Yazdani, S., Bencheikh, F., Komatsu, R., Yokoyama, S., Kamiya, T., and Adachi, C.

Subjects
DISTRIBUTED feedback lasers, ACTIVE medium, OPTOELECTRONIC devices, EMISSION control, OPTICAL diffraction, LASER beams, LASERS
Abstract

The control of laser emission angles in laser devices is essential for many optoelectronic and photonic applications such as optical sensing and displays. In this context, we studied the light diffraction pattern of laser beams in a one-dimensional sampled distributed feedback resonator having organic gain media. The gratings consist of the repetition of supercells having a mixed-order sampled grating in which 1st-order gratings surround a 2nd-order grating. The experimental results showed that the diffraction angles of the laser beams are quite diverse depending on the supercell structures. We demonstrate that the interval of the diffraction angle (θ) of the laser beams is inversely proportional to the length of the supercell experimentally and theoretically. By tuning the length of supercells as well as the length of 1st-order and 2nd-order regions, the interval θ was tuned from 0.1° to 43° with the different arc emission patterns. With the reduction of θ, i.e., the longer 1st-order region, a significant decrease in the laser threshold was obtained, resulting in the lowest lasing threshold of 2.5 ± 0.1 μJ/cm2 with ∼3.5 ns of a long pulse width excitation source. [ABSTRACT FROM AUTHOR]

Published
2022
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14. 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.

Published
2019
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16. 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

17. 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

18. 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

25. 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

26. 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

30. M022 Performance evaluation of microslide and open channel on VITROS XT 7600 – Establish a clinical testing system for clinical chemistry in the event of a disaster-

Author

Yokoyama, S., primary, Kikuchi, R., additional, Matsuyama, H., additional, Ohashi, K., additional, Watarai, R., additional, Hayashi, G., additional, Numata, Y., additional, Hagiwara, T., additional, Kobayashi, T., additional, Ando, Y., additional, and Matsushita, T., additional

Published
2022
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36. 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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49. Development of shape monitoring system using SMA dipole antenna on a deployable membrane structure

Author

Terada, Y., Yokoyama, S., Sakamoto, H., Torisaka, Ayako, Hayashi, Daisuke, Kawasaki, Shigeo, and Nishii, Naoki

Subjects
Materials science, Acoustics, Aerospace Engineering, macromolecular substances, 02 engineering and technology, 01 natural sciences, Shape memory alloy, Radiation pattern, law.invention, Printed circuit board, Data acquisition, 0203 mechanical engineering, law, 0103 physical sciences, polycyclic compounds, Dipole antenna, 010303 astronomy & astrophysics, Computer Science::Information Theory, Patch antenna, 020301 aerospace & aeronautics, fungi, Membrane, Shape-memory alloy, SMA, Antenna, biological sciences, sense organs, Antenna gain, Shape sensing
Abstract

Accepted: 2019-04-03, 資料番号: SA1190179000

Published
2019

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