Various types of traumatic injuries of the middle ear structures can be caused by either direct or indirect forces through the external auditory canal, auditory tube, and by forces transmitted indirectly through the skull. Diagnosis of middle ear injuries should be established by precise history taking, audiological tests, x-ray examinations including polytomography and high resolution CT. The most common trauma of the middle ear is perforation of the tympanic membrane due to blunt trauma, penetrating injury or barotrauma. Traumatic perforations of the tympanic membrane tend to heal rapidly but the long standing perforations can be repaired by surgery or by cauterization with several kinds of patches. Discontinuity of the ossicular chain is not always readily diagnosed. However, in any doubt of ossicular injuries surgical exploration of the middle ear must be considered. The methods of repair should be versatile in order for continuity to be re-established. Rupture of the inner ear windows can be caused by even minor traumas such as head concussion, baratrauma, sneezing or coughing. Exploration of the middle ear cavity is mandatory and sealing of the ruptured round and oval window have been recommended.

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　The purpose of this study was to translate tacit knowledge about enhancement of self-preservation skills in the water into explicit knowledge, and to clarify the aspects that should be taught and evaluated. Based on the findings, an attempt was made to devise a teaching theory for the design of university swimming lessons aimed at enhancing such skills. The participants were 17 experienced teachers who teach university swimming lessons, and SCAT was used to analyze the textual data to create a story line for each lesson in self-preservation skills. From the obtained storylines, we extracted important and common concepts of teaching aspects and how to assess them, and classified them into categories. The number of concepts generated by the text analysis was 36, and from among them, 2 small categories, 2 medium categories, 5 large categories and 5 core categories were generated. The 5 core categories were “Reasons for teaching self-preservation skills in the water in university swimming classes”, “Aims of university swimming classes”, “Self-preservation skills in the water to be taught in university swimming classes”, “Methods of teaching self-preservation skills in the water”, and “Methods of assessing selfpreservation skills in the water”. Based on these core categories, a conceptual diagram of the relationship between water self-preservation skills and methods for teaching and assessing them was presented. In order to enhance self-preservation skills in the water in university swimming classes, it became clear that it was necessary to design classes using four basic theories: 1) to enhance knowledge of water safety, 2) to enhance water movement skills, 3) to enhance the ability to cope with drowning situations, and 4) to assess water movement skills and knowledge of water safety. Also, it was considered necessary to incorporate the following 3 points when designing university swimming lessons for this purpose :1) to set the teaching objectives of the lesson, keeping in mind the type of lesson and the skill level of the students; 2) to set the ratio of the teaching of the 4 basic theories in each lesson in order to achieve the desired teaching objectives; 3) to provide time each hour for students to assess their selfpreservation skills in the water in order to monitor their own skill level.

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When we obtain public acceptance for the peaceful use of atomic power, one way is to compare the radiation risks with other various risks, for example risks from occupational or daily-life accidents. In the present paper, the fatality risks from accidents in various leisure sports and accidents in daily life were assessed during the period of 1981-1989.
The risks were calculated as the ratio of the number of deaths to the population of all Japan or the population that participated in each leisure sport, respectively. The average actual death numbers per year during 1981-1989 examined were 413 in fishing and 387 in swimming at sea, the risk being 1.0×10^-5 and 2.5×10^-5, as expressed in participated population. The most dangerous sport is sky-diving from a paraglider or parachute, although the actually participated population is very small. The average risk is about 1.0×10^-5 in all leisure sports, 1.1×10^-5 in aquatics, 6.4×10^-6 in land sports and 4.0×10^-5 in aerosports.
These risks were compared with fatality risks from occupational accidents (8.5×10^-5), car accidents (1.0×10^-4) and the accidents at home (5.0×10^-5) as well as cancer risk per Sv proposed by ICRP.

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目的：フィンスイミングによる痛みは足関節に生じやすいため，足関節痛と関連の高い要因を明らかにし，足関節の外傷・障害予防の一助とすることを目的とした。

方法：2016年度フィンスイミング日本選手権出場選手314名のうち中学生以上の選手を対象とした。出場選手が所属する全チーム代表者に質問紙を送付し，79名（男子49名，女子30名）の有効回答を得た。質問項目は，足関節痛，足関節捻挫の既往，自覚的な足関節の緩さや不安定感，足関節・体幹トレーニングの実施率，泳動作中の足関節の使い方の意識，および自覚的な発症要因とした。統計処理は，足関節痛の有無と名義尺度，比率尺度との関連について二項ロジスティック回帰分析を行った。有意水準は5％とした。

結果：現在の足関節痛（27名）は，自覚的な足関節の緩さ（27名）の中でも，特にフィン使用時の足関節の緩さ（23名）との間に有意に高い関連がみられた（オッズ比28.5，95％CI 7.7－105.9）。現在・過去の有痛者36名の自覚的な発症要因は足関節の緩さ（12名）が最多であり，足関節捻挫の既往（3名）もみられた。トレーニング実施率は体幹68.4％に対し，足関節は26.6％と低かった。

結論：フィン使用時の自覚的な足関節の緩さはフィンスイミングによる足関節痛と高い関連が明らかとなり，更に自覚的な発症要因としても足関節の緩さが最多であったことから，足関節の緩さへの対策の必要性が示唆された。

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　The purpose of this study was to verify the educational effectiveness and outcomes of university swimming classes for enhancing self-preservation skills in the water, which had been formulated by Yamanaka et al. (2022), and to re-structure the teaching theory for these skills based on their design. Educational effectiveness was evaluated in terms of changes in students' water movement skills and a questionnaire survey. For analysis of changes in water movement skills, we used the results of 10-minute drifting, 12-minute swimming, and Stallman's skill check. Also, to analyze the educational outcomes of the class, we qualitatively analyzed the assignments in the class report to the students. The results of the skill measurements showed that the percentage of students who successfully achieved the 10-minute drifting and 12-minute swimming tasks was significantly higher in the last class session than in the first. In addition, for all measurements, the percentage of students who answered “I can do” in the last class session was significantly higher than in the first. Analysis of the class reports confirmed that the students were able to achieve the set objectives and tasks of the class. Consequently, the teaching theory for self-preservation ability in the water was re-structured by: (1) giving students the opportunity to experience coping with water disaster based on water movement skills and knowledge of underwater safety, (2) letting students experience various aquatic activities, (3) allowing students to recognize their own self-preservation skills in the water, and (4) enhancing the ability of students to cope with water disaster situations by allowing them to think of their own responses.

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大学や専門学校を含めた高等教育の授業において，「学修者本位の教育への転換」の必要性が掲げられているが授業設計という観点からすると，大学の水泳授業は改善する余地が大きい．本調査では，水泳教育の前提であり欠かすことができない水中での自己保全能力を高めることをねらいとした大学水泳授業を設計することを目的とした．設計した授業では，大学の定める大学体育授業の理念と教育目標を達成できるように以下の６つの授業目標を設定した．①水中での運動の特性を理解する，②水中運動技能・水中安全の知識・水難状況への対応力を高める，③様々な水中運動・スポーツを通して，水の危険性を体感する，④主体的に学習することを通して水中での自己保全能力を高める，⑤水中安全に関わる能力や知識を客観的・主観的に評価する，⑥他者の安全を確保するための技能や知識を高める．この授業目標を達成するために知識・技能・水難状況への対応力の３つの観点から課題を設定し，効果的に学修，定着させるために，「事前学修」，「水中運動技能練習」，「技能テスト」，「水難状況への対応力を高める指導」，「事後評価」などの授業構成パートを設定し，その構成と割合を設計した．「水難状況への対応力を高める指導」では，授業で学生が身につける水中安全能力の課題と想定される危険や高めるべき資質や能力を予め設定し，それを支援する様々な

や水中運動を教材として配置した．また，「事前学修」，「水中運動技能練習」，「技能テスト」，「事後評価」を通して，学生が自身の課題の把握，水中運動技能の練習計画の作成，練習計画の実践，技能テストによる技能レベルの評価，自身の取り組みを改善するPDCAサイクルを回し，学生が主体的に授業を進めるようにした．実施教材の点から，本研究で設計した水泳授業を参考に，目的に沿って内容を修正することで，多くの大学が，学生が主体的に水中での自己保全能力を高める大学水泳授業を実施できると考えられる．

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Since competitive fin swimming using bi-fin is a relatively new sport, there are no research about swimming motion considering the characteristic of the fin. Therefore players determine their swimming motion based on their own sense and experience. In this research, a simulation model to assess the swimming motion was constructed by extending the swimming human simulation model SWUM. In this model, the fin was modeled as a series of five rigid plates. These plates were connected by virtual springs and dampers, by which forces according to relative distance and velocity acted.

Fin's elasticity was also represented by springs and dampers, by which torques according to relative angle and angular velocity acted. The fin parameters such as the shape, the rigidity, and the hydrodynamic coefficients, were determined by comparing the experimental results of the deformation and the force measurement with the results simulated in the same condition. Fin swimming was simulated in a standard crawl motion. It was found that the body was unstable.

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We describe herein our hospital’s treatment policy for patients with otitis media cholesteatoma associated with a semicircular canal fistula and report the test results for semicircular canal fistula sites, fistula depths, postoperative bone conduction, and hearing.

All the patients had a semicircular canal fistula associated with otitis media cholesteatoma and underwent surgery between August 2010 and April 2016 at the Department of Otorhinolaryngology of Kansai Electric Hospital. The semicircular canal fistula depths were classified according to the Dornhoffer and Milewski classification as I, IIa, IIb, and III, and 17 ears with a depth classification of IIa or higher were investigated. Eleven ears were newly operated on, and the other 6 underwent re-operations. All the re-operated ears had been previously operated on at other hospitals. In principle, a canal wall up tympanoplasty was used as the operative method, in view of the importance of the patients’ postoperative quality of life. In all the cases, fistula treatment was conducted in a one-stage operation as the final step of the operation, and the fistula was covered with a piece of thinly sliced cartilage.

The fistula sites were the external semicircular canal in 15 ears and the external semicircular canal plus the anterior semicircular canal and external semicircular canal plus the posterior semicircular canal in 1 ear each. The fistula depths were IIa, IIb and III in 11, 2 and 4 ears, respectively.

Decreased postoperative bone conduction was observed in 5 (29.4%) of the 17 ears that were examined; the decrease in bone conduction in these 5 ears was within the range of 15 dB. Hearing was improved in 9 (56.3%) of the 16 evaluable ears; 1 ear was not evaluable. Postoperative dry eardrums were confirmed in all 17 ears.

Severe postoperative reductions in bone conduction can be prevented by careful and appropriate fistula treatment.

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