389 research outputs found

    Self-organized aggregation and traveling wave in a kinetic transport model for run-and-tumble bacteria (Mathematical Analysis in Fluid and Gas Dynamics)

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    The self-organized pattern formation of run-and-tumble chemotactic bacteria is numerically investigated based on a kinetic transport equation considering internal adaptation dynamics and a finite tumbling duration. It is confirmed that the volcano-like aggregation profile is generated due to the coupling of diffusion and internal adaptation dynamics occurring at a large adaptation-time scaling. Moreover, an extended Keller-Segel model, derived by the asymptotic analysis of the kinetic model at the large adaptation-time scale, can describe the volcano effect well. It is also found that when the mean run length of the bacteria becomes large, the volcano effect is more enhanced and unexpectedly, different types of pattern formation (i.e., standing and traveling bands) arise at very large adaptation times. The mathematical mechanism of the novel pattern formation should be an important future study. This paper is a resume of previous studies by the author in S. Yasuda, Bull. Math. Biol. 84, 113 (2022) and K. Adachi and S. Yasuda, Springer Proc. Math. Stat. 429, 235 (2023)

    Acute effect of static stretching on power output during concentric dynamic constant external resistance leg extension.

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    Yamaguchi, T., K. Ishii, M. Yamanaka, and K. Yasuda. Acute effect of static stretching on power output during concentric dynamic constant external resistance leg extension. J. Strength Cond. Res. 20(4):804–810. 2006.—The purpose of the present study was to clarify the effect of static stretching on muscular performance during concentric isotonic (dynamic constant external resistance [DCER]) muscle actions under various loads. Concentric DCER leg extension power outputs were assessed in 12 healthy male subjects after 2 types of pretreatment. The pretreatments included (a) static stretching treatment performing 6 types of static stretching on leg extensors (4 sets of 30 seconds each with 20-second rest periods; total duration 20 minutes) and (b) nonstretching treatment by resting for 20 minutes in a sitting position. Loads during assessment of the power output were set to 5, 30, and 60% of the maximum voluntary contractile (MVC) torque with isometric leg extension in each subject. The peak power output following the static stretching treatment was significantly (p < 0.05) lower than that following the nonstretching treatment under each load (5% MVC, 418.0 ± 82.2 W vs. 466.2 ± 89.5 W; 30% MVC, 506.4 ± 82.8 W vs. 536.4 ± 97.0 W; 60% MVC, 478.6 ± 77.5 W vs. 523.8 ± 97.8 W). The present study demonstrated that relatively extensive static stretching significantly reduces power output with concentric DCER muscle actions under various loads. Common power activities are carried out by DCER muscle actions under various loads. Therefore, the result of the present study suggests that relatively extensive static stretching decreases power performance

    El debate literario sobre la modernidad en el Jaón de preguerra y posguerra: Yasuda Yojuro y Kobayashi

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    Japanese critics of modernism Kobayashi Hideo and Yasuda Yojuro wrote an important chapter in the history of the formation of the consciousness of identity in the field of literary semiotics in Japan. It is necessary to review their contribution in the present context of the global debate on national and cultural identities. Kobayashi has had a say on current critics of the sort of Karatani Kojin, who has made an appreciative reception of the former�s critic way of thinking. Here the author of this essay claims that the position of Kobayashi in favour of the aesthetic category of beauty should not be misunderstood for sheer aestheticism, but on the contrary it may imply a positive stance towards a restatement of meaning in a desemanticised world of pure profit.En la historia de la construccion de la identidad literaria japonesa, el periodo inmediatamente anterior y posterior a la Guerra del Pacifico han marcado un punto de impasse. En el marco de la �gsuperacion de la modernidad�h que domina el contorno japones de los anos treinta y cuarenta. Los estetas Kobayashi Hideo y Yasuda Yoj.r. participan de manera activa, el segundo defendiendo un esteticismo de retorno a la idiosincrasia japonesa y reactivo frente a la modernidad, y el primero defendiendo una identidad que subsiste en el subsuelo de lo impostado, sea moderno extranjero o escritura pretendidamente �gjaponesa�h. La posteridad ha demostrado que la postura de Kobayashi, heredero de la critica cultural de Natsume S.seki, y precursor de criticos contemporaneos como Yoshimoto Takaaki o Karatani K.jin, marca el eje central de la conciencia especificamente japonesa sobre la modernidad literaria

    Towards a re-examination of methodology in the historical study of Japanese language teaching (II) : The 'discussion' between Yasuda and Matsuoka, and some other issues

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    小論は、2002年度目本語教育学会春季大会シンポジウムに端を発する安田敏朗と松岡弘の「論争」を批判的に検討したものである。松岡は、安田が日本語教育史研究の「これから」に対して行った批判に反批判を加え、コメニウスと山口喜一郎の言語教育観・教授法の類似性を根拠に言語教育の普遍性を主張し、日本語教育を論難する安田に反論する。しかし、筆者は、この反論に於ける松岡による安田の見解の不当な矮小化、歴史的文脈を無視したコメニウスと山口の対比の不的確性、松岡のテキスト解釈の狭さを指摘し、さらに、こうした松岡の解釈が安田や、同様に日本語教育を批判する駒込武に対する"報復感情"に起因することを批判した。また、松岡や関正昭の駒込・安田批判が、日本語教育の部外者に向けられながら内部者には為されない不徹底さを指摘し、その閉鎖的な体質を批判するとともに、歴史研究者からも学ぶこと及び日本語教育に無理解な言説に対する批判の必要性を提唱した。In this paper, the author critically examines a 'discussion' between Toshiaki Yasuda and Hiroshi Matsuoka originating from a symposium held at the Society for Teaching Japanese as a Foreign Language Academic Conference in 2002. Matsuoka criticized Yasuda's comment on the future of the historical study of Japanese language teaching. He insisted on the universality of language teaching based on the comparison of Comenius with Kiichiro Yamaguchi in the field of pedagogical thought and teaching methods. However, it is pointed out that Matsuoka made an unfair low evaluation of Yasuda's comment, an inappropriate comparison beween Comenius and Yamaguchi, and a narrow interpretation of Yamaguchi's textbook. Moreover, t he author criticizes this evaluation and interpretation since it seems to be caused by a feeling of retaliation for the criticisms against Japanese language teaching from Yasuda and Takeshi Komagome. In addition, the author also points out and criticizes an inconsistent attitude of Matsuoka and Masaaki Seki in that they criticized Japanese language teaching outsiders (Yasuda and Komagome) yet make no criticism against insiders. Finally, the author advocates the necessity of learning from historians and for criticism against a discourse lacking in understanding of Japanese language teaching

    Unsteady solute dispersion in the presence of reversible and irreversible reactions

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    In an unsteady pulsatile non-Newtonian fluid past a tube with a thin wall layer, the dispersion of a narrow uniform slug of injected solute over a cross-section is examined. At the interface between the mobile fluid phase and the immobile wall phase, both irreversible and reversible reactions have been adopted. The Carreau-Yasuda model is used to describe the fluid's rheology. The impacts of fluid rheology and reaction parameters on the concentration profiles in the fluid-and wall-phases and the three transport coefficients, viz, the depletion coefficient (K0), the convection coefficient (K1), the dispersion coefficient (K2) in the fluid phase are predicted numerically. A considerable shift in the behaviour of K1 and K2 with a higher reaction rate may be observed in the transient stage. The axial dispersion of mobile-phase concentration in the unsteady Carreau-Yasuda II fluid model is significantly larger than in Poiseuille and steady Carreau-Yasuda II fluid models, and flow pulsatility on the immobile-phase concentration is prominent upstream at a longer time. In addition, the peak value of the mobile-phase section-mean concentration is consistently lower than in other fluid models. This study could help researchers to understand the drug delivery in blood vessels and pulmonary mechanical ventilation. © 2022 The Author(s)

    Unsteady solute dispersion in the presence of reversible and irreversible reactions

    No full text
    In an unsteady pulsatile non-Newtonian fluid past a tube with a thin wall layer, the dispersion of a narrow uniform slug of injected solute over a cross-section is examined. At the interface between the mobile fluid phase and the immobile wall phase, both irreversible and reversible reactions have been adopted. The Carreau-Yasuda model is used to describe the fluid's rheology. The impacts of fluid rheology and reaction parameters on the concentration profiles in the fluid- and wall-phases and the three transport coefficients, viz, the depletion coefficient (K-0), the convection coefficient (K-1), the dispersion coefficient (K-2) in the fluid phase are predicted numerically. A considerable shift in the behaviour of K-1 and K(2 )with a higher reaction rate may be observed in the transient stage. The axial dispersion of mobile-phase concentration in the unsteady Carreau-Yasuda II fluid model is significantly larger than in Poiseuille and steady Carreau-Yasuda II fluid models, and flow pulsatility on the immobile-phase concentration is prominent upstream at a longer time. In addition, the peak value of the mobile-phase section-mean concentration is consistently lower than in other fluid models. This study could help researchers to understand the drug delivery in blood vessels and pulmonary mechanical ventilation. (C) 2022 The Author(s) Published by the Royal Society. All rights reserved
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