Convex Approximation of Bounded Rational Equilibria

In this paper, we consider the existence of a sequence of convex sets that has an approximation property for the equilibrium sets in the bounded rational environments. We show that the bounded rational equilibrium multivalued map is approximated with arbitrary precision in the abstract framework, a parameterized class of "general games" together with an associated abstract rationality function that is established by Anderlini and Canning (2001). As an application, we show that the existence of a selection for some bounded rational equilibria on a discontinuous region P when P is a perfect set.Convex Approximation, Bounded Rational Equilibria, Selection

Geometric trade-off between contractile force and viscous drag determines the actomyosin-based motility of a cell-sized droplet

動きまわる人工細胞、その鍵は摩擦にあり --細胞が狭い空間を利用して運動する仕組みを解明--. 京都大学プレスリリース. 2022-07-21.Cell migration in confined environments is fundamental for diverse biological processes from cancer invasion to leukocyte trafficking. The cell body is propelled by the contractile force of actomyosin networks transmitted from the cell membrane to the external substrates. However, physical determinants of actomyosin-based migration capacity in confined environments are not fully understood. Here, we develop an in vitro migratory cell model, where cytoplasmic actomyosin networks are encapsulated into droplets surrounded by a lipid monolayer membrane. We find that the droplet can move when the actomyosin networks are bound to the membrane, in which the physical interaction between the contracting actomyosin networks and the membrane generates a propulsive force. The droplet moves faster when it has a larger contact area with the substrates, while narrower confinement reduces the migration speed. By combining experimental observations and active gel theory, we propose a mechanism where the balance between sliding friction force, which is a reaction force of the contractile force, and viscous drag determines the migration speed, providing a physical basis of actomyosin-based motility in confined environments

形状忠実な頭部物理モデルとFEモデルによる脳外傷発生メカニズムの解明に関する研究

金沢大学理工研究域現状のヘルメットやエアバッグなどの防護用品の設計基準は,脳の変形を考慮せずに,単に頭部を剛体とみなしたときの並進加速度のみから算出されており,実際の脳外傷の発生にそれほど関係がないと言われている。そこで,脳外傷の発生メカニズムを解明し,それに基づく設計基準を制定することが,事故の犠牲者を減らす上で重要となる。そこで,衝撃を受ける頭部の外傷発生メカニズムを解明するために,主に頭部FEモデルを用いた研究が行われているが,生体実験データの取得が困難であるため,その妥当性は十分に検証されていない。一方で,球等の単純形状の物理モデルを用いた実験も行われているが,実際に人体で起きる現象を把握できるとは言い切れない。そこで,本研究では特定個体の医用画像から構築された頭部の三次元CADデータからラピッドプロトタイピング技術を利用することにより,形状忠実な頭部の物理モデルを製作するとともに,同一形状を有する有限要素モデルも構築した。さらに,前年度において頭部物理モデルにより行われた衝撃実験結果により有限要素モデルの妥当性を検証した。その結果,従来研究での個体が異なる屍体実験結果を用いた検証では困難であった,頭部FEモデルの流体-構造の連成系の扱い,脳と頭蓋の境界条件および材料特性などの誤差要因の影響について検討し,定量的に同定を行うことが出来た。さらに,同定された頭部FEモデルを用いた高速度衝撃シミュレーションにより,その発生部位および形態に特徴を有する脳挫傷は頭蓋骨の解剖学的形状の影響で衝撃部位により好発部位が異なることを明らかにした。研究課題/領域番号:18800015, 研究期間(年度):2006-2007出典：「形状忠実な頭部物理モデルとFEモデルによる脳外傷発生メカニズムの解明に関する研究」研究成果報告書　課題番号18800015（KAKEN：科学研究費助成事業データベース（国立情報学研究所））（https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-18800015/)を加工して作

Research and Development of Computer Software to Create Story Problems to Promote the Children’s Individual Development (VIII)

これまでの和差に関する算数文章題の研究より，答えを求めるための演算と，言語的な物語が示唆する演算が異なる場合に児童の理解が混乱しているとの知見が得られている。本研究では，和差の算数文章題がその背景としての物語において含んでいる一つの和と二つの差の関係（１和２差関係）の把握が不十分であることがこの混乱の原因と考え，この１和２差の構造を可視化する全体部分関係を用いて，１回の和差に関するすべての算数文章題が，一つの和と二つの差を含んでいることを児童に理解させるための授業とその授業に則した演習支援ソフトウェアの開発およびその実践利用を行った。開発した授業およびソフトウェアを小学２年生１クラス，小学３年生２クラスにおいて実施し，その実施可能性を確認した。また，作問課題をプレテストおよびポストテストとして，逆思考問題の作成能力に関して顕著な効果が見られることを確認した・これは，児童の文章題に対する構造的理解が深まったことを示唆する結果であり，本研究の目的は達成されたと考えられる。In this research project, we developed computer software to allow a pupil to operate sentences of arithmetic word problems, numerical expressions, and whole-part relations. We then and designed a curriculum to promote student comprehension of the structure of arithmetic word problems by using this software. We conducted practical teaching following the curriculum and based on the software for one second-grade class and two third-grade classes, with 10 class sessions in total. Through the practical use, we have confirmed that the software and curriculum were useful to promote student comprehension of the structure of arithmetic word problems by measuring their problem-posing performance

Illustrated checklist of fishes from the Shubuto River System, southwestern Hokkaido, Japan

A checklist of fish fauna, comprising 40 species representing 15 families and 9 orders, was compiled from field, museum, and literature surveys of the Shubuto River System, southwestern Hokkaido, Japan. This area approximates the boundary of southern/northern affinities of Japanese freshwater fishes. All primary freshwater species, are listed except for Gymnogobius castaneus and all anadromous and marine amphidromous species that are scientifically presumed to occur naturally in the area. The list contains two invasive exotic species, Cyprinus carpio and Oncorhynchus mykiss, and two Siberian primary freshwater species, Lefua nikkonis and Barbatula toni, which are thought to mark the boundary of southern and northern affinities of Japanese freshwater fishes. Rhynchocypris perenurus, another Siberian primary freshwater species with a similar presumed range, was not recorded. The voucher specimen species included Platycephalus sp. 2, which is suggested to have the northernmost extended range

The Effect of Seat Back Inclination on Spinal Alignment in Automotive Seating Postures

Experimental studies have demonstrated a relationship between spinal injury severity and vertebral kinematics, influenced by the initial spinal alignment of automotive occupants. Spinal alignment has been considered one of the possible causes of gender differences in the risk of sustaining spinal injuries. To predict vertebral kinematics and investigate spinal injury mechanisms, including gender-related mechanisms, under different seat back inclinations, it is needed to investigate the effect of the seat back inclination on initial spinal alignment in automotive seating postures for both men and women. The purpose of this study was to investigate the effect of the seat back inclination on spinal alignments, comparing spinal alignments of automotive seating postures in the 20\ub0 and 25\ub0 seat back angle and standing and supine postures. The spinal columns of 11 female and 12 male volunteers in automotive seating, standing, and supine postures were scanned in an upright open magnetic resonance imaging system. Patterns of their spinal alignments were analyzed using Multidimensional Scaling presented in a distribution map. Spinal segmental angles (cervical curvature, T1 slope, total thoracic kyphosis, upper thoracic kyphosis, lower thoracic kyphosis, lumbar lordosis, and sacral slope) were also measured using the imaging data. In the maximum individual variances in spinal alignment, a relationship between the cervical and thoracic spinal alignment was found in multidimensional scaling analyses. Subjects with a more lordotic cervical spine had a pronounced kyphotic thoracic spine, whereas subjects with a straighter to kyphotic cervical spine had a less kyphotic thoracic spine. When categorizing spinal alignments into two groups based on the spinal segmental angle of cervical curvature, spinal alignments with a lordotic cervical spine showed significantly greater absolute average values of T1 slope, total thoracic kyphosis, and lower thoracic kyphosis for both the 20\ub0 and 25\ub0 seat back angles. For automotive seating postures, the gender difference in spinal alignment was almost straight cervical and less-kyphotic thoracic spine for the female subjects and lordotic cervical and more pronounced kyphotic thoracic spine for the male subjects. The most prominent influence of seatback inclination appeared in Total thoracic kyphosis, with increased angles for 25\ub0 seat back, 8.0\ub0 greater in spinal alignments with a lordotic cervical spine, 3.2\ub0 greater in spinal alignments with a kyphotic cervical spine. The difference in total thoracic kyphosis between the two seatback angles and between the seating posture with the 20\ub0 seat back angle and the standing posture was greater for spinal alignments with a lordotic cervical spine than for spinal alignments with a kyphotic cervical spine. The female subjects in this study had a tendency toward the kyphotic cervical spine. Some of the differences between average gender-specific spinal alignments may be explained by the findings observed in the differences between spinal alignments with a lordotic and kyphotic cervical spine

Fibrinogen–platelet ratio and pancreatic cancer

Background : Several prognostic factors were reported in pancreatic cancer. The fibrinogen–platelet ratio (FPR) was reported as a prognostic factor of resectable gastric cancer. In this report, the FPR was evaluated in patients with resectable pancreatic cancer. Methods : Between 2004 and 2019, 163 patients with curative resection for pancreatic cancer were enrolled. Cases of non-curative resection were excluded. The FPR was calculated using the preoperative plasma fibrinogen and the platelet counts and the cut-off value was determined by receiver operating characteristic (ROC) curve analysis. The patients were divided into high and low FPR groups according to this cut-off value. Results : The cut-off value of FPR was 25.2. Among age, sex, body mass index (BMI), and surgical factors including surgery type, volume of blood loss and surgery time, there was no significant difference between the two groups. Patients in the low FPR group had significantly better overall survival (OS) and relapse-free survival (RFS) compared with the high FPR group (P 300 U / ml, and receipt of adjuvant chemotherapy were independent risk factors for OS and DFS. Conclusions : The FPR might be a prognostic factor for patients with resectable pancreatic cancer