教師なし深層学習を用いた腎病理所見評価手法の開発

京都大学新制・論文博士博士(医学)乙第13501号論医博第2260号京都大学大学院医学研究科医学専攻(主査)教授 小林 恭, 教授 中本 裕士, 教授 黒田 知宏学位規則第4条第2項該当Doctor of Medical ScienceKyoto UniversityDFA

Trade and mergers in the presence of firm heterogeneity

We investigate the role of firm heterogeneity in considering profitability and desirability of mergers in the international economy. Analysis shows that higher trade costs make only crossborder mergers profitable whereas larger firm heterogeneity is likely to increase both domestic and cross-border mergers. Furthermore, it is shown that whether or not a merger leads to merger waves depends on the types of firms involved in it. It is also demonstrated that larger firm heterogeneity can reduce the discrepancy between profitability and desirability of mergers when the trade cost is sufficiently low.M&As, trade, firm heterogeneity, Cournot competition

Horizontal mergers, firm heterogeneity, and R&D investments

We investigate the incentive and the welfare implications of a merger when heterogeneous oligopolists compete both in process R&D and on the product market. We examine how a merger affects the output, investment, and profits of firms, whether firms have merger incentives, and, if so, whether such mergers are desirable from the viewpoint of social welfare. We also derive equilibrium configurations and explore their welfare properties.

Spatially Inhomogeneous Superconducting State near Hc2H_{\rm c2} in UPd2_2Al3_3

We have performed $^{27}$Al-NMR measurements on single-crystalline UPd$_2$Al$_3$ with the field parallel to the $c$ axis to investigate the superconducting (SC) properties near the upper critical field of superconductivity $H_{\rm c2}$. The broadening of the NMR linewidth below 14~K indicates the appearance of the internal field at the Al site, which originates from the antiferromagnetically ordered moments of U 5$f$ electrons. In the SC state well below $\mu_0H_{\rm c2}$ = 3.4~T, the broadening of the NMR linewidth due to the SC diamagnetism and a decrease in the Knight shift are observed, which are well-understood by the framework of spin-singlet superconductivity. In contrast, the Knight shift does not change below $T_{\rm c}(H)$, and the NMR spectrum is broadened symmetrically in the SC state in the field range of 3~T $< \mu_0 H < \mu_0 H_{\rm c2}$. The unusual NMR spectrum near $H_{\rm c2}$ suggests that a spatially inhomogeneous SC state such as the Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) state would be realized.Comment: 5 pages, 5 figure

Interpretation of some Yb-based valence-fluctuating crystals as approximants to a dodecagonal quasicrystal

The hexagonal ZrNiAl-type (space group: P-62m) and the tetragonal Mo2FeB2-type (space group: P4/mbm) structures, which are frequently formed in the same Yb-based alloys and exhibit physical properties related to valence-fluctuation, can be regarded as approximants of a hypothetical dodecagonal quasicrystal. Using Pd-Sn-Yb system as an example, a model of quasicrystal structure has been constructed, of which 5-dimensional crystal (space group: P12/mmm, aDD=5.66 {\AA} and c=3.72 {\AA}) consists of four types of acceptance regions located at the following crystallographic sites; Yb [00000], Pd[1/3 0 1/3 0 1/2], Pd[1/3 1/3 1/3 1/3 0] and Sn[1/2 00 1/2 1/2]. In the 3-dimensional space, the quasicrystal is composed of three types of columns, of which c-projections correspond to a square, an equilateral triangle and a 3-fold hexagon. They are fragments of two known crystals, the hexagonal {\alpha}-YbPdSn and the tetragonal Yb2Pd2Sn structures. The model of the hypothetical quasicrystal may be applicable as a platform to treat in a unified manner the heavy fermion properties in the two types of Yb-based crystals.Comment: 19 pages, 6 figure