長時間超新星爆発計算とSuper-Kamiokande IVにおける超新星爆発探索

京都大学新制・課程博士博士(理学)甲第23004号理博第4681号新制||理||1671(附属図書館)京都大学大学院理学研究科物理学・宇宙物理学専攻(主査)准教授 WENDELL Roger, 教授 中家 剛, 准教授 久徳 浩太郎学位規則第4条第1項該当Doctor of ScienceKyoto UniversityDFA

Long-term gravitational wave asteroseismology of supernova: from core collapse to 20 seconds postbounce

We use an asteroseismology method to calculate the frequencies of gravitational waves in a long-term core-collapse supernova simulation, with a mass of 9.6 $M_\odot$. The simulation, which includes neutrino transport in general relativity is performed from core-collapse, bounce, explosion and cooling of protoneutron stars (PNSs) up to 20 s after the bounce self-consistently. Based on the hydrodynamics background, we calculate eigenmodes of the PNS oscillation through a perturbation analysis on fluid and metric. We classify the modes by the number of nodes and find that there are several eigenmodes. In the early phase before 1 s, there are a low-frequency g-mode around 0.5 kHz, a mid-frequency f-modes around 1 kHz, and high-frequency p-modes above them. Beyond 1 s, the g-modes drop too low in frequency and the p-modes become too high to be detected by ground-based interferometers. However, the f-mode persists at 1 kHz. We present a novel fitting formula for the ramp-up mode, comprising a mixture of g-mode and f-mode, using postbounce time as a fitting parameter. Our approach yields improved results for the long-term simulation compared to prior quadratic formulas. We also fit frequencies using combinations of gravitational mass and radius of the PNS. We test three types of fitting variables: compactness, surface gravity, and average density. We present results of the time evolution of each mode and the fitting for three different ranges, from 0.2 to 1, 4, and 20 s for each formula. We compare the deviation of the formulas from the eigenmodes to determine which fitting formula is the best. In conclusion, any variable fits the eigenmodes well to a similar degree. Comparing 3 variables in detail, the fitting with compactness is slightly the best among them. We also find that the fitting using less than 1 s of simulation data cannot be extrapolated to the long-term frequency prediction.Comment: submitted to PR

Genetic relationships and expected responses for genetic improvement of carcass traits of Berkshire pigs

The Berkshire pig (Sus domestica L.) breed has thin muscle fibers and excellent water-holding capacity. The Berkshire meat makes it widely accepted in the Japanese premium pork market. This study evaluates the accuracy of improving carcass quality with the use of live animal records of Berkshire pigs. Traits analyzed in live animals were: body weight at 60 days of age (W60), age at finish (AGF), daily weight gain from birth to finish (DG), back fat thickness at finish (BFTF), and loin eye area at finish (LEAF), and in carcasses were: carcass weight, loin eye area (LEA), and subcutaneous fat thickness (SCF) at some points, using the records of 4,773 purebred Berkshire pigs. Variance components for the traits were estimated according to the animal model by the Restricted Maximum Likelihood (REML) procedure using the VCE6 program (Neumaier and Groeneveld, 1998). Correlated responses were also calculated. Genetic correlations of back fat thickness (BFT) in live animals with SCF in slaughtered animals were strong, whereas that of LEA between live and slaughtered animals was low. The expected gains by actual selection including W60 and BFTF as selection criterion were superior to other selections. Therefore, selection of live animals at an early stage of growth would be conducive to the production of high quality meat

Observing Supernova Neutrino Light Curves with Super-Kamiokande. III. Extraction of Mass and Radius of Neutron Stars from Synthetic Data

Neutrinos are guaranteed to be observable from the next Galactic supernova (SN). Optical light and gravitational waves are also observable, but may be difficult to observe if the location of the SN in the Galaxy or the details of the explosion are unsuitable. The key to observing the next SN is to first use neutrinos to understand various physical quantities and then link them to other signals. In this paper, we present Monte Carlo sampling calculations of neutrino events from Galactic SN explosions observed with Super-Kamiokande. The analytical solution of neutrino emission, which represents the long-term evolution of the neutrino light curve from SNe, is used as a theoretical template. It gives the event rate and event spectrum through inverse beta decay interactions with explicit model parameter dependence. Parameter estimation is performed on these simulated sample data by fitting least squares using the analytical solution. The results show that the mass, radius, and total energy of a remnant neutron star produced by an SN can be determined with an accuracy of ∼ 0.1 M⊙, ∼1 km, and ∼ 10⁵¹ erg, respectively, for a Galactic SN at 8 kpc

A four-dimensional organoid system to visualize cancer cell vascular invasion

Yanagisawa, K.; Konno, M.; Liu, H.; Irie, S.; Mizushima, T.; Mori, M.; Doki, Y.; Eguchi, H.; Matsusaki, M.; Ishii, H. A Four-Dimensional Organoid System to Visualize Cancer Cell Vascular Invasion. Biology 2020, 9, 361

Transient Receptor Potential 1 Regulates Capacitative Ca2+ Entry and Ca2+ Release from Endoplasmic Reticulum in B Lymphocytes〉

Capacitative Ca2+ entry (CCE) activated by release/depletion of Ca2+ from internal stores represents a major Ca2+ influx mechanism in lymphocytes and other nonexcitable cells. Despite the importance of CCE in antigen-mediated lymphocyte activation, molecular components constituting this mechanism remain elusive. Here we demonstrate that genetic disruption of transient receptor potential (TRP)1 significantly attenuates both Ca2+ release-activated Ca2+ currents and inositol 1,4,5-trisphosphate (IP3)-mediated Ca2+ release from endoplasmic reticulum (ER) in DT40 B cells. As a consequence, B cell antigen receptor–mediated Ca2+ oscillations and NF-AT activation are reduced in TRP1-deficient cells. Thus, our results suggest that CCE channels, whose formation involves TRP1 as an important component, modulate IP3 receptor function, thereby enhancing functional coupling between the ER and plasma membrane in transduction of intracellular Ca2+ signaling in B lymphocytes

チイキザイジュウコウレイシャ ニ オケル テントウヨボウジココウリョクカン ト HDL コレステロール オヨビ シンタイノウリョク トノ カンレン コスゲムラオウダンケンキュウ

背景 : 本研究の目的は,転倒予防自己効力感とHDLコレステロール及び身体能力との関連性を調べることであった。方法 : 対象者は山梨県小菅村に在住する65歳以上の高齢者339名で,本調査には132名(38.9%)が参加した。移動能力として10m全力歩行,最大一歩幅,40cm踏台昇降を,バランス能力としてつぎ足歩行を測定した。血液性状の中で,主要なアウトカムとして,HDLコレステロールを用いた。転倒予防自己効力感は,10項目,4リッカートスケールからなる質問紙で評価した。研究デザインは,転倒恐怖の有無による2群間比較の横断研究である。結果 : 転倒予防自己効力感とHDLコレステロールの間に有意な関連はなかったが,転倒予防自己効力感が低い群では有意に移動能力が低かった。また,膝痛や腰痛を伴う男性では,転倒予防自己効力感が低かった。結論 : 自己効力感とHDLコレステロールとの関連は認められなかったが,本研究は地域在住で独立生活を営む高齢者に限定されているため,今後,良くデザインされた大規模な観察研究が必要だと考えられた。Background : The aim of the current study was to clarify relationships between self-efficacy and high-density lipoprotein cholesterol (HDL-C) and physical strength.Methods : Target participants were 339 elderly residents aged 65 years or older from Kosuge Village, Yamanashi Prefecture in Japan. One hundred and thirty two persons participated in the study (38.9%). Outcome measurements included the 10-m walking time, the maximal step length and 40-cm step test as moving ability, the tandem gait as balance ability, and HDL-C. Fall-prevention self-efficacy (FPSE) was evaluated using a questionnaire that examined 10 items (actions) and 4 Likert scale. A total of 40 points could be awarded. This research design was a cross-sectional study that divided the elderly into two groups by the existence of a fear of falling.Results : Although there was no significant relationship between fall-prevention self-efficacy and HDL-C, we demonstrated that a group with poor self-efficacy had significantly deteriorated moving ability and that only one male participant with knee pain and/or lumbago exhibited poor self-efficacy.Conclusions : We could not find significant relationships between self-efficacy and HDL-C. But this study is limited to the independent elderly people in a local area, and further studies should be conducted to detect the relationships