著者

高橋 太 中野 慎也 南 拓人 谷口 陽菜実 中島 涼輔 松島 政貴 清水 久芳 藤 浩明

雑誌

JpGU-AGU Joint Meeting 2020

巻号頁・発行日

2020-03-13

---

Secular variation (SV) of the Earth's magnetic field is governed by the advection and diffusion processes of the magnetic field within the fluid outer core. The IGRF (International Geomagnetic Reference Field) offers the average SV for the next five years to come, which has been estimated in various methods. In general, forecasting the evolution of a non-linear system like the geodynamo in the Earth's core is an extremely difficult task, because the magnetic field generation processes are controlled by the complex interaction of the core flows and the generated magnetic field. Data assimilation has been a promising scheme forecasting the geomagnetic SV as demonstrated in literatures (Kuang 2010, Fournier et al. 2015), where time dependency is controlled by a numerical dynamo model. While Ensemble Kalman Filter (EnKF) has been a popular method for data assimilation in geomagnetism, we apply a different data assimilation procedure, that is, four-dimensional, ensemble-based variational scheme, 4DEnVar. Applying the 4DEnVar scheme iteratively, we have derived a candidate SV model for the latest version of the IGRF. In evaluating SV, two forecasting strategies are tested, in which core flows are assumed to be steady or time-dependent. The former approach is favored in Fournier et al. (2015), where the magnetic field evolves kinematically by the flows prescribed to be time-independent in the initialization step. On the other hand, we have adopted linear combination of magnetohydrodynamic (MHD) models to construct a candidate as the best forecast (Minami et al. 2020). It is likely that which strategy is more suitable to forecasting SV depends on assimilation scheme and/or numerical dynamo model. However, we have little knowledge on the issue at present. In this study, we investigate results of MHD and kinematic dynamo runs with a 4DEnVar scheme in order to have a grasp of the properties of the scheme in the 5-year forecast process. Also, MHD and kinematic runs are compared to infer internal dynamics responsible for SV in the geomagnetic field.

著者

南 拓人 中野 慎也 高橋 太 松島 政貴 中島 涼輔 清水 久芳 谷口 陽菜実 藤 浩明

雑誌

JpGU-AGU Joint Meeting 2020

巻号頁・発行日

2020-03-13

---

The thirteenth generation of International Geomagnetic Reference Field (IGRF-13) was released by International Association of Geomagnetism and Aeronomy (IAGA) in December, 2019. Prior to the release, we submitted a secular variation (SV) candidate model for IGRF-13 using a data assimilation scheme and a magnetohydrodynamic (MHD) dynamo simulation code (Minami et al. submitted to EPS special issue for IGRF-13). Our candidate SV model was evaluated by IAGA Division V Working Group V-MOD and contributed to the final IGRF-13SV model with the optimized weight. This became the first contribution to the IGRF community from research groups in Japan. This was enabled by bilateral corroboration between Japan and France; in our data assimilation scheme, we used the French main field model (Ropp et al. 2020), which was developed from magnetic observatory hourly means, and CHAMP and Swarm-A satellite data. We adopted an iterative assimilation algorithm based on four-dimensional ensemble-based variational method (4DEnVar) (Nakano 2020), which linearizes outputs of our MHD dynamo simulation (Takahashi 2012; 2014) with respect to the deviation from a dynamo state vector at an initial condition. The data vector for the assimilation consists of the poloidal scalar potential of the geomagnetic field at the Earth’s core surface, and flow velocity field slightly below the core surface, which was calculated by presuming magnetic diffusion in the boundary layer and tangentially magnetostrophic flow below it (Matsushima 2020). Dimensionless time of numerical geodynamo was adjusted to the actual time by comparison of secular variation time scales. For estimation of our IGRF-13SV candidate model, we first generated an ensemble of dynamo simulation results from a free dynamo run. We then assimilated the ensemble to the data with a 10-year assimilation window from 2009.50 to 2019.50 through iterations, and finally forecasted future SV by linear combination of the future extension parts of the ensemble members. We generated our final SV candidate model by linear fitting for the best linear combination of the ensemble MHD dynamo simulation members from 2019.50 to 2025.00. We derived errors of our SV candidate model by one standard deviation of SV histograms based on all the ensemble members. In the presentation, we plan to report our IGRF project through the bilateral corroboration with France, and describe our SV candidate model.

著者

中島 涼輔 吉田 茂生

雑誌

JpGU-AGU Joint Meeting 2020

巻号頁・発行日

2020-03-13

---

Magnetohydrodynamic (MHD) shallow water linear waves are examined on a rotating sphere with a background toroidal magnetic field expressed as B0Φ=B0sinθ, where B0 is constant, θ is the colatitude and Φ is the azimuth. The MHD shallow water equations are often used in studying the dynamics of the solar tachocline (e.g. Gilman & Dikpati, 2002[1]; Márquez-Artavia et al., 2017[2]) and sometimes the outermost Earth's core (Márquez-Artavia et al., 2017[2]; Nakashima, Ph.D. thesis, 2020[3]) and exoplanetary atmosphere (e.g. Heng & Workman, 2014[4]). In this poster, we especially focus on the propagation mechanisms and the force balances of polar trapped waves and unstable modes (Márquez-Artavia et al., 2017[2]; Nakashima, Ph.D. thesis, 2020[3]).Comprehensive searches for eigenmodes yield two polar trapped modes when the main magnetic field is weak (the Lehnert number α=VA/2ΩR2<0.5, where VA is the Alfvén wave velocity, Ω is the rotation rate and R is the sphere radius). One is the slow magnetic Rossby waves, which propagate eastward for zonal wave number m≧2 (Márquez-Artavia et al., 2017[2]). As the Lamb's parameter ε=4Ω2R2/gh→0 (where g is the gravity acceleration and h is the equivalent depth), these branches asymptotically approach the eigenvalues of two-dimensional slow magnetic Rossby waves. Another is newly discovered westward polar trapped modes (Nakashima, Ph.D. thesis, 2020[3]).In the case when α>0.5 (the background field is strong), these novel westward modes merge with the westward-propagating fast magnetic Rossby waves. In addition, only when m=1, polar trapped unstable modes appear due to the interaction between these fast magnetic Rossby waves and westward-propagating slow magnetic Rossby waves. These growth modes are believed to be the polar kink (Tayler) instability (Márquez-Artavia et al., 2017[2]).In order to easily understand the propagation mechanisms and the force balances of polar trapped modes, we investigate a cylindrical model around a pole with an artificial boundary condition. This model provides the approximate dispersion relations and eigenfunctions of polar trapped modes, and indicates that stable polar trapped modes are governed by magnetostrophic balance and that the metric magnetic tension force causes the difference between the slow magnetic Rossby waves and the novel westward modes. For m=1 and α>0.5, the balance between Coriolis and Lorentz forces is disrupted and the part of magnetic tension with which Coriolis force can not compete induces kink instability.[ Reference ][1] Gilman, P. A., Dikpati, M. (2002) Astrophys. J., 576, 1031. doi: 10.1086/341799[2] Márquez-Artavia, X., Jones, C. A., Tobias, S. M. (2017) Geophys. Astrophys. Fluid Dyn., 111, 282. doi: 10.1080/03091929.2017.1301937[3] Nakashima, R. (2020) Ph.D. thesis, Kyushu University. http://dyna.geo.kyushu-u.ac.jp/HomePage/nakashima/pdf/doctoral_thesis.pdf[4] Heng, K., Workman, J. (2014) Astrophys. J. Sup., 213, 27. doi: 10.1088/0067-0049/213/2/27

著者

中島 涼輔 吉田 茂生

雑誌

JpGU-AGU Joint Meeting 2020

巻号頁・発行日

2020-03-13

---

Magnetohydrodynamic (MHD) shallow water linear waves are investigated over a rotating sphere with an imposed equatorially antisymmetric toroidal magnetic field: B0Φ=B0sinθcosθ, where B0 is a constant, θ is the colatitude and Φ is the azimuth. This system can imitatively represent the dynamics of a liquid metal within a stably stratified layer at the top of the Earth's core, which was detected through seismological surveys (e.g. Helffrich & Kaneshima, 2010[1]) and also has been deduced from geophysical and geochemical knowledge (e.g. Buffett & Seagle, 2010[2]; Pozzo et al., 2012[3]; Gubbins & Davies, 2013[4]; Brodholt & Badro, 2017[5]). Because slowly propagating waves in the liquid core can result in geomagnetic secular variations, comparison between exhaustive studies of MHD waves in a rotating stratified fluid and observations of geomagnetic fluctuations should provide constraints on the obscure stratified layer in the outermost core (e.g. Braginsky, 1993[6]; Buffett, 2014[7]).The adopted configuration of the background field complicates solving the eigenvalue problem of linear waves due to the emergence of an Alfvén continuum and critical latitudes unless dissipation effects are taken into account. These result from non-dissipative Alfvén resonance, which occurs only when B0Φ/sinθ depends on θ, that is, regular singular points appear in the differential equation of linear problems. The solutions of the continuum are required to express the transient evolution of an arbitrary initial disturbance (e.g. Case, 1960[8]; Goedbloed & Poedts, 2004[9]). We can confirm numerically and analytically that introducing magnetic diffusion eliminates these Alfvén continuous modes and their singular structures around critical latitudes (Nakashima, Ph.D. thesis, 2020[10]).For the Earth's core-like parameter (B0≃0.5—5mT and magnetic diffusivity η≃1m2/s), westward polar trapped modes are obtained as eigenmodes, which have a period of around from several to 1000 years. We may be able to observe these modes as geomagnetic secular variations in high latitude regions, if the strength of stratification in the stratified layer is close to the estimate of Buffett (2014)[7]. The analyses of recent geomagnetic models and paleomagnetic data in terms of such waves could confirm the robustness of previous estimates of the properties of the layer.[ Reference ][1] Helffrich, G., Kaneshima, S. (2010) Nature, 468, 807. doi: 10.1038/nature09636[2] Buffett, B. A., Seagle, C. T. (2010) J. Geophys. Res., 115, B04407. doi: 10.1029/2009JB006751[3] Pozzo, M., Davies, C., Gubbins, D., Alfè, D. (2012) Nature, 485, 355. doi: 10.1038/nature11031[4] Gubbins, D., Davies, C. J. (2013) Phys. Earth Planet. Inter., 215, 21. doi: 10.1016/j.pepi.2012.11.001[5] Brodholt, J., Badro, J. (2017) Geophys. Res. Lett., 44, 8303. doi: 10.1002/2017GL074261[6] Braginsky, S. I. (1993) J. Geomag. Geoelectr., 45, 1517. doi: 10.5636/jgg.45.1517[7] Buffett, B. (2014) Nature, 507, 484. doi: 10.1038/nature13122[8] Case, K. M. (1960) Phys. Fluids, 3, 143. doi: 10.1063/1.1706010[9] Goedbloed, J. P., Poedts, S. (2004) Principles of magnetohydrodynamics: with applications to laboratory and astrophysical plasmas, Cambridge Univ. Press, Cambridge.[10] Nakashima, R. (2020) Ph.D. thesis, Kyushu University. http://dyna.geo.kyushu-u.ac.jp/HomePage/nakashima/pdf/doctoral_thesis.pdf

出版者

京都医事衛生社

巻号頁・発行日

no.315, 1920-06

著者

大木 幹文

出版者

日本耳鼻咽喉科免疫アレルギー学会

雑誌

耳鼻咽喉科免疫アレルギー (ISSN:09130691)

巻号頁・発行日

vol.33, no.1, pp.1-6, 2015 (Released:2015-03-25)

参考文献数

21

---

鼻アレルギーに対する局所療法には鼻腔洗浄法,点鼻液滴下療法,定量噴霧器噴霧療法,ネブライザー療法などがある。鼻洗浄は抗原の回避の意味合いがある。薬液治療法はまず薬液を直接点鼻する方法から始まった。ステロイド療法をコントローラとして考えると初期のベータメタゾン点鼻薬は,血中コーチゾール値が高値になることがある。フロンガスを用いた定量噴霧器が開発されたが,オゾン層破壊の危険のため使用が禁止となり,定量液体スプレーが現在は主体となっている。しかしながら,鼻粘膜への刺激や,液漏れという副作用も認められる。ドラッグディバリーの観点から,欧米ではエアロゾル化を見直した脱フロンの噴霧液が多く市販される様になり,鼻粘膜の吸着も広範囲に均一となる。また,抗ヒスタミン薬とステロイド薬の合剤による噴霧器もその有用性が検討されてきている。本邦においても内服薬のみでは無く局所薬の有益性の検討をさらに進めるべきである。

著者

小坂,共栄

出版者

日本地質学会

雑誌

地質学論集

巻号頁・発行日

no.13, 1976-12-30

---

The Middle Miocene to Early Pleistocene marine sediments have a wide distribution in the northern part of Nagano Prefecture. In this area basin-forming movements became conspicuous since the Aoki age. Consequently three large sedimentary basins, that is the Komiji, the Takafu and the Hikage basins, were formed. These basins have a general trend of NNE-SSW. Since the Middle Pliocene time, another new tectonic movement took place in the central part of this area. The Orihashi sedimentary basin with a NE-SW direction was formed as a result of this movement. Deposits of the early stage in this basin were a large quantity of andesitic lava flows and pyroclastics (Arakurayama pyroclastics), which covered unconformably the lower Shigarami formation in some parts. It is remarkable that the younger basin-forming movement of the Pliocene time was characterized by a violent volcanism. Similar volcanism and tectonism are found also in the Hijiri (Komiji) and the Togakushi (Hikage) districts.

著者

嘉村 哲郎

出版者

デジタルアーカイブ学会

雑誌

デジタルアーカイブ学会誌 (ISSN:24329762)

巻号頁・発行日

vol.4, no.2, pp.150-153, 2020 (Released:2020-04-25)

参考文献数

4

---

中小規模のデジタルアーカイブの課題の一つに,データ保存と管理に必要な情報システムや機器の継続性があげられる。そこで,情報システムやメンテナンス費用,運用にかかる属人的要素の課題を解決する案として,オープンライセンスでデータをWeb公開・共有を可能とするWikimedia CommonsとWikidataの利用を提案する。本稿では,東京藝術大学音楽学部大学史史料室の資料を例に,これらWiki群を使用したデータ公開と活用『GLAM WIKI』について報告する。

著者

増田 周子

出版者

關西大學文學會

雑誌

關西大學文學論集 (ISSN:04214706)

巻号頁・発行日

vol.55, no.2, pp.55-73, 2005-10-15

著者

渥美 公秀

雑誌

情報処理学会研究報告グループウェアとネットワークサービス(GN)

巻号頁・発行日

vol.1994, no.33(1994-GN-006), pp.37-42, 1994-04-28

---

集団で意思決定を行う場合には必ずしも「三人寄れば文殊の知恵」にはならない。Janis (72,19)がアメリカの政策決定過程に着目しこの現象を集団的浅慮(oupthi)と名付けて以来、社会心理学の分野では様々な研究が行なわれてきた。本稿では集団的浅慮現象とその後の研究を紹介するとともに、従来の研究に含まれていた「情報処理パラダイムの陥穽」を指摘する。最後に、今後の集団研究の方向性として「意味構築パラダイム」への移行を展望する。

著者

川田 研郎 河野 辰幸 中島 康晃

出版者

一般社団法人 日本消化器内視鏡学会

雑誌

日本消化器内視鏡学会雑誌 (ISSN:03871207)

巻号頁・発行日

vol.59, no.1, pp.70-80, 2017 (Released:2017-01-20)

参考文献数

54

---

近年,欧米においてはバレット食道が急速に増加しており,本邦においても今後増加することが懸念されている.バレット食道を診断するためには,十分に食道胃接合部を伸展させ,下部食道柵状血管の下端もしくは胃の襞の上縁を確認し,胃から連続する円柱上皮を確認する.SSBEの表在癌は右前壁に多いとされ,まず通常内視鏡で発赤・凹凸不整の所見を見落とさないことが重要である.深達度診断には白色光観察に加え,画像強調内視鏡,拡大内視鏡,超音波内視鏡,食道造影が用いられる.凹凸のほとんどない0-Ⅱbや0-Ⅱa,基部にくびれを有する0-Ⅰ型,浅い陥凹を有する0-Ⅱc型は粘膜癌を示唆する.酢酸併用画像強調+拡大内視鏡は癌の側方伸展の診断に有用である.バレット食道癌の深達度診断は治療方針をたてるのに重要である.一部のT1a-DMM癌と粘膜下層癌には転移が見られるため,内視鏡治療の適応拡大は慎重に行う必要がある.

著者

山口 佳巳

出版者

日本建築学会

雑誌

日本建築学会計画系論文集

巻号頁・発行日

no.689, 2013-07

著者

黒川 清

出版者

一般社団法人 日本内科学会

雑誌

日本内科学会雑誌 (ISSN:00215384)

巻号頁・発行日

vol.89, no.12, pp.2407-2409, 2000-12-10 (Released:2008-06-12)

参考文献数

14

著者

富山 慶典

出版者

群馬大学社会情報学部

雑誌

群馬大学社会情報学部研究論集 (ISSN:13468812)

巻号頁・発行日

no.4, pp.55-67, 1997-07-28

---

Some relationship among the individual choice competence, the number of individuals in the group, its decision rule and the collective choice competence was initially investigated in Condorcet's Jury Theorem. Although several researchers have devloped the theorem in different directions, they in common assume implicitly one collective choice area and introduce only the individual choice competence for the area. In reality, however, there may exist multiple collective choice areas such as 'management strategy and personnel changes planning' and the individual choice competencies may be different for the corresponding area such that 'he/she is good at management strategy but not personnel changes planning'. Under the multiplicity of choice areas and the difference in competencies, how should the group assign what members in it to what collective choice area? Tomiyama (1991) extends the basic model under Jury Theorem to the model of two collective choice areas and formulates in general the group two-decomposition problem. It also gives a solution to this problem under the complete homogeneity assumption that all of the members in the group have the same competence of individual choice for all of the collective choice areas. This paper analyses the problem under the heterogeneity assumption. It is proved that individual rationality and social rationallty may not be compatible. The high-competence decomposition is used to represent individual rationality, and the maximum-sum decomposition and the minimum-difference decomposition are used to represent social rationality. Finally, some unsolved problems are showed.

著者

章清著

出版者

上海古籍出版社

巻号頁・発行日

2004

著者

東 武瑠

出版者

慶應義塾大学大学院社会学研究科

雑誌

慶應義塾大学大学院社会学研究科紀要 : 社会学・心理学・教育学 : 人間と社会の探究 (ISSN:0912456X)

巻号頁・発行日

no.85, pp.1-18, 2018

---

論文

著者

Yui SHIMOMI Yasuhiko KONDO

出版者

Japanese Association for Laboratory Animal Science

雑誌

Experimental Animals (ISSN:13411357)

巻号頁・発行日

pp.19-0161, (Released:2020-06-30)

被引用文献数

3

---

Among the intact male rats, a subpopulation has been found to show little or no sexual behavior, even after experiencing several mating sessions. This study investigated whether sexually sluggish (SS) males show behavioral differences from normal copulatory (NC) males, other than those concerning sexual behavior. The olfactory preference of males was measured through the time spent displaying nose-poking behavior directed at sexually active males and estrous females for odor exploration in a three-chamber apparatus. Both the NC and SS males showed a significant preference for the odor of estrous females compared with that of male odors. However, SS males spent significantly less time nose-poking estrous females than NC males. The food-finding test was performed after overnight fasting. Our findings showed that all the NC males found the buried pellet within 5 min, whereas over 60% of the SS males failed to find it. The males were also tested for their ability to find a buried bag containing soiled bedding from estrous female cages. The bag was found by 80% of NC males, but only by 20% of SS males. Our results suggest that SS and NC male rats differ not only in sexual behavior but also in other functions such as olfaction.

著者

奥村 映仁 飛田 尚慶 大場 誠悟 中尾 紀子 朝比奈 泉

出版者

THE JAPANESE SOCIETY FOR JAW DEFORMITIES

雑誌

日本顎変形症学会雑誌 (ISSN:09167048)

巻号頁・発行日

vol.20, no.1, pp.25-29, 2010-04-15 (Released:2012-03-02)

参考文献数

12

被引用文献数

2 7

---

In this case report, we present a surgical orthodontic treatment performed for an aged female. The patient was a 62-year-old female with chief complaints concerning occlusal disharmony, dyslalia, and aesthetic disturbance. As a result of various analysis, the patient was diagnosed with mandibular prognathism accompanied by deep bite and reversed occlusion. Due to the venerability of the patient, she presented numerous risks. The patient was treated with Le Fort I osteotomy, sagittal split ramus osteotomy and genioplasty. To acquire and to maintain a stable postoperative occlusion, close cooperation with the prothodontist was carried out. Postoperatively, the patient's chief complaints were improved and she demonstrated satisfactory progress after one year. The results of this case report indicate that treatment of a jaw deformity with surgical orthodontic procedures is effective for the improvement of occlusal disorders as well as aesthetic problems. If there are no general health problems, this treatment may be applied irrespective of the patient's age.

出版者

リック

雑誌

技術営業leaders

巻号頁・発行日

vol.43, no.3, pp.53-55, 2016-03

著者

萩行 正嗣 柴田 知秀 黒橋 禎夫

出版者

一般社団法人情報処理学会

雑誌

情報処理学会研究報告. NL,自然言語処理研究会報告 (ISSN:09196072)

巻号頁・発行日

vol.185, pp.45-52, 2008-05-15

参考文献数

14

被引用文献数

1

---

近年、インターネット環境の普及とともに数多くの人がブログを通じて情報を発信するようになっている。それに伴い、大量に存在するブログから面白いものを探し出すことが困難になってきている。本研究では表層・語彙的特徴量に基づき、ブログの面白さを分析する手法を提案する。まず、ブログの記事から文字長などの表層的特徴量や評価表現などの語彙的特徴量といった様々な特徴量を抽出する。そして,これらを特徴量として与えてSVRを用いた機械学習を行なうことで、ブログの面白さを推定する。独自に設置したブログを用いて収集した249件のブログ記事とそれを採点したものを用いて実験を行なったところ,ベースラインを上回る精度を達成することができた。また、面白さの個人差の問題についてはドメインアダプテーションを用いることで対処した。最後に、学習されたモデルからブログの面白さの要因について考察を行なった。