337 research outputs found

    Moduli space of rank three logarithmic connections on the projective line with three poles

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    In this paper, we describe the moduli space of rank three parabolic logarithmic connections on the projective line with three poles for any local exponents. In particular, we show that the family of moduli spaces of rank three parabolic phi-connections on the projective line with three poles is isomorphic to the family of A^{(1)*}_2-surfaces in Sakai's classification of Painlev\'e equations. Through this description, we investigate the relation between the apparent singularities and underlying parabolic bundles. In an appendix, we also describe the moduli space of parabolic Higgs bundles of the above setting and the Hitchin fibration.Comment: 46 pag

    Physical properties of portland cement based concrete exposed at a depth of 3520 m in the Nankai Trough

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    Concrete is widely used in large-scale construction of submarine infrastructure because of its high strength, durability, and ease of handling. However, knowledge of its durability in deep seawater is lacking. In the deep sea, materials are exposed to high pressures and low temperatures, which may cause early deterioration of concrete over time. Concrete materials may also be affected by the chemical composition of seawater, which induces the leaching of calcium. In situ exposure tests are therefore important for understanding degradation processes in the deep sea. In this study, Portland cement based concrete specimens were placed at a depth of 3520 m on the northern edge of the Nankai Trough in 2018 and retrieved in 2019, in the deepest exposure testing conducted to date. Here we provide an outline of the tests, describe the physical properties of materials exposed to deep seawater, freshwater, and air, and discuss possible concrete degradation mechanisms

    Effect of Dy substitution in the giant magnetocaloric properties of HoB2_{2}

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    Recently, a massive magnetocaloric effect near the liquefaction temperature of hydrogen has been reported in the ferromagnetic material HoB2_{2}. Here we investigate the effects of Dy substitution in the magnetocaloric properties of Ho1x_{1-x}Dyx_{x}B2_{2} alloys (x\textit{x} = 0, 0.3, 0.5, 0.7, 1.0). We find that the Curie temperature (T\textit{T}C_{C}) gradually increases upon Dy substitution, while the magnitude of the magnetic entropy change |ΔSM\Delta \textit{S}_{M}| at T\textit{T} = TC\textit{T}_{C} decreases from 0.35 to 0.15 J cm3^{-3} K1^{-1} for a field change of 5 T. Due to the presence of two magnetic transitions in these alloys, despite the change in the peak magnitude of |ΔSM\Delta \textit{S}_{M}|, the refrigerant capacity (RC\textit{RC}) and refrigerant cooling power (RCP\textit{RCP}) remains almost constant in all doping range, which as large as 5.5 J cm3^{-3} and 7.0 J cm3^{-3} for a field change of 5 T. These results imply that this series of alloys could be an exciting candidate for magnetic refrigeration in the temperature range between 10-50 K.Comment: 19 pages, 5 figures, 2 table

    AI-Josyu: Thinking Support System in Class by Real-time Speech Recognition and Keyword Extraction

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    In this paper, we present a thinking support system, AI-Josyu. This system also operates as a class support system which helps to teachers for lightening their work. AI-Josyu is implemented based on media-driven real-time content management framework. The system links real world media and legacy media contents together. In resent years, it is easier to collect a large amount of various kinds of data which are created with sensors in the real world. The system realizes interconnection and utilization of legacy media contents. The legacy media contents are generated and scattered on the Internet. The framework has four modules, which are called “acquisition,†“extraction,†“selection,†and “retrieval.†The real world media and the legacy media contents are interconnected by these modules. This interconnection includes semantic components. This system records teacher's voice of its lecture in real time and presents retrieved legacy media contents corresponding to subject of the lecture. By this presentation, preparing of the legacy contents is not required. This system automatically retrieves and shows the legacy media contents. This system helps students to understand contents of the lecture. In addition, the system attends to expansion of ideas. We constructed the system and conducted the demonstration in class. It shows that the system is helpful to teacher and students for expansion of thinking

    Short or Irregular Sleep Duration in Early Childhood Increases Risk of Injury for Primary School-Age Children: A Nationwide Longitudinal Birth Cohort in Japan

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    The aim of this study was to investigate the longitudinal relationship between shorter or irregular sleep duration (SD) in early childhood and increased risk of injury at primary school age using data from a nationwide survey in Japan. We categorized SD into seven groups: 6 h, 7 h, 8 h, 9 hrs, 10 or 11 h, >12 h, and irregular, based on questionnaire responses collected at 5.5 years old. The relationship between SD and incidence of injury at 5.5-nine years of age is shown. In addition, we completed a stratified analysis on children with or without problematic behavior at eight years old. We included 32,044 children, of which 6369 were classified as having an injury and 25,675 as not having an injury. Logistic regression model showed that shorter or irregular SD categories were associated with an increased adjusted odds ratio (aOR) for injuries (6 h: aOR 1.40, 95% confidence interval (CI) 1.19-1.66, 7 h: aOR 1.10, 95% CI, 0.98-1.23, 8 h: aOR 1.13, 95% CI, 1.02-1.26, irregular: aOR 1.26, 95% CI 1.10-1.43). The same tendency was observed with shorter or irregular SD in subgroups with or without behavioral problems. Shorter or irregular sleep habits during early childhood are associated with injury during primary school age
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