118 research outputs found

    Fano threefolds of large Fano index and large degree

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    We classify Q-Fano threefolds of Fano index > 2 and big degree.Comment: 38 page

    Short-term stability in refractive status despite large fluctuations in glucose levels in diabetes mellitus type 1 and 2

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    Purpose: This work investigates how short-term changes in blood glucose concentration affect the refractive components of the diabetic eye in patients with long-term Type 1 and Type 2 diabetes. Methods: Blood glucose concentration, refractive error components (mean spherical equivalent MSE, J0, J45), central corneal thickness (CCT), anterior chamber depth (ACD), crystalline lens thickness (LT), axial length (AL) and ocular aberrations were monitored at two-hourly intervals over a 12-hour period in: 20 T1DM patients (mean age ± SD) 38±14 years, baseline HbA1c 8.6±1.9%; 21 T2DM patients (mean age ± SD) 56±11 years, HbA1c 7.5±1.8%; and in 20 control subjects (mean age ± SD) 49±23 years, HbA1c 5.5±0.5%. The refractive and biometric results were compared with the corresponding changes in blood glucose concentration. Results: Blood glucose concentration at different times was found to vary significantly within (p0.05). Minor changes of marginal statistical or optical significance were observed in some biometric parameters. Similarly there were some marginally significant differences between the baseline biometric parameters of well-controlled and poorly-controlled diabetic subjects. Conclusion: This work suggests that normal, short-term fluctuations (of up to about 6 mM/l on a timescale of a few hours) in the blood glucose levels of diabetics are not usually associated with acute changes in refractive error or ocular wavefront aberrations. It is therefore possible that factors other than refractive error fluctuations are sometimes responsible for the transient visual problems often reported by diabetic patients

    Historical Sources of Institutional Trajectories in Economic Development: China, Japan, and Korea Compared

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    This essay provides a game-theoretic, endogenous view of institutions, and then applies the idea to identify the sources of institutional trajectories of economic development in China, Japan, and Korea. It stylizes the Malthusian-phase of East Asian economies as peasant-based economies in which small families allocated their working time between farming on small plots - leased or owned - and handcrafting for personal consumption and markets. It then compares institutional arrangements across these economies that sustained otherwise similar economies. It characterizes the varied nature of the political states of Qing China, Tokugawa Japan, and Yi Korea by focusing on the way in which agricultural taxes were enforced. It also identifies different patterns of social norms of trust that were institutional complements to, or substitutes for, political states. Finally, it traces the path-dependent transformations of these state-norm combinations along subsequent transitions to post-Malthusian phases of economic growth in the respective economies

    Room-Temperature Plastic Deformation of Strontium Titanate Crystals Grown from Different Chemical Compositions

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    Oxide materials have the potential to exhibit superior mechanical properties in terms of high yield point, high melting point, and high chemical stability. Despite this, they are not widely used as a structural material due to their brittle nature. However, this study shows enhanced room-temperature plasticity of strontium titanate (SrTiO3) crystals through the control of the chemical composition. It is shown that the deformation behavior of SrTiO3 crystals at room temperature depends on the Sr/Ti ratio. It was found that flow stresses in deforming SrTiO3 crystals grown from a powder with the particular ratio of Sr/Ti = 1.04 are almost independent of the strain rate because of the high mobility of dislocations in such crystals. As a result, the SrTiO3 crystals can deform by dislocation slip up to a strain of more than 10%, even at a very high strain rate of 10% per second. It is thus demonstrated that SrTiO3 crystals can exhibit excellent plasticity when chemical composition in the crystal is properly controlled

    Deformation behaviour in micro sheet hydroforming process

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    Crystallization and melting of poly(butylene terephthalate) and poly(ethylene terephthalate) investigated by fast-scan chip calorimetry and small angle X-ray scattering

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    © 2020 Elsevier Ltd The crystallization and melting behaviors of poly(butylene terephthalate) (PBT) and poly(ethylene terephthalate) (PET) were examined by Hoffman-Weeks (H–W), Gibbs-Thomson (G-T), and thermal Gibbs-Thomson (t-G-T) plots constructed by using fast-scan calorimetry and small-angle X-ray scattering. With PBT and PET, neither an H–W nor a G-T plot could be utilized for the determination of the equilibrium melting point (TM0) of chain-extended infinite-size crystals. The thermal Gibbs-Thomson plot utilizes the change in the melting point and the heat of fusion of chain-folded crystals during the secondary stage of isothermal crystallization. TM0 was determined from a t-G-T plot, and the results were in good agreement with the literature values for PBT and PET. G-T and t-G-T plots suggested a temperature-dependent folding surface free energy (σe), as has been proposed by Hoffman et al. The σe values obtained with G-T and t-G-T plots support the consistency of the analysis
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