Toward Normalization of Relations with Japan: The Strategy of North Korea, circa 1950 to 1961

North Korea is still a strictly secluded state and little is known of its past and present though recent research using documents from countries in the former Soviet bloc has produced a number of breakthroughs especially in the discussion of the origins of the Korean War. Among others, history of relations between North Korea and Japan is most unexplored. One might assume that North Korea has had little interest in developing relations with Japan because of the adversary political ideologies between them. Focusing on the early history of North Korea, the present paper demonstrates that this assumption is quite wrong. North Korea needed the Japanese industrial products and technical know-how from the start of its state formation. This gave its leader, Kim Il-sung a good economic reason for establishing official relations with Japan. However, in the early period, he had little political power to execute his own policy toward Japan. His action had to follow the Soviet grand strategy toward the West. By 1961 he achieved a great success in his attempts. This afforded him a promising prospect for the military built-up using Japanese products, that is, developments of the nuclear and missile programs in the later periods.

Regional Income Inequality in the Post-War Japan

In his seminal work on national development and regional inequality, Williamson (1965) predicts that regional income inequality will pass through three distinct phases as a nation moves through the early development stages to maturity. In the early stages of economic development, regional income inequality will increase, largely because of the disequilibrating effects of factor mobility. This will be followed by a period of stability, characterized by a relatively high level of inequality between regions. Finally, a lessening of regional inequality will set in as the national economy matures and equilibrating forces take effect. This overall process, if plotted against national economic development, will result in a bell-shaped or inverted U-shapes curve. The early stages of development are also associated with rapid urbanization, though with a shift toward population dispersion as the economy matures. Other stylized facts in the process of development include industrialization, demographic transition, and changing inequality of income among population subgroups (Alonso, 1980). The concentration of population in and around large cities is usually accompanied by an increase in regional income inequality. Some researchers have argued that this population concentration and concurrent increase in regional inequality does not impede economic development, and may in fact favor it. Nonetheless, many national governments have introduced policies of balanced regional development. The main objective of this paper is to measure regional income inequality in the post-war Japan using Williamson?s weighted coefficient of variation. Based on prefectural population and GDP data, it investigates longer-term trends in regional income inequality. A sectoral decomposition analysis is also performed to examine the extent to which each industrial sector contributes to the overall weighted coefficient of variation. We hope to gain a deeper understanding of the relationship between national development, industrialization, and regional inequalities in the post-war Japan.

MIRAI Architecture for Heterogeneous Network

One of the keywords that describe next-generation wireless communications is "seamless." As part of the e-Japan Plan promoted by the Japanese Government, the Multimedia Integrated Network by Radio Access Innovation project has as its goal the development of new technologies to enable seamless integration of various wireless access systems for practical use by 2005. This article describes a heterogeneous network architecture including a common tool, a common platform, and a common access. In particular, software-defined radio technologies are used to develop a multiservice user terminal to access different wireless networks. The common platform for various wireless networks is based on a wireless-supporting IPv6 network. A basic access network, separated from other wireless access networks, is used as a means for wireless system discovery, signaling, and paging. A proof-of-concept experimental demonstration system is available

キイロショウジョウバエ由来のチオレドキシン還元酵素のC未端テトラペプチド配列は、ヒト肺由来のチオレドキシン還元酵素では酸化還元活性を示さない

The isozymes of mammalian thioredoxin reductase (TrxR) contain the penultimate selenocysteineresidue (SeCys) in the redox-active C-terminal tetrapeptide, -Gly-Cys-SeCys-Gly (end). Amutant form of the mammalian enzyme TrxR-X498C in which SeCys is replaced with Cys showsa dramatically decreased catalytic activity, suggesting that SeCys residue plays an integral role inthe catalysis. In contrast, TrxR of the fruit fly, Drosophila melanogaster, has no selenium in the corresponding C-terminal redox sequence, which instead of SeCys has flanking serine residues in the terminal sequence, -Ser-Cys-Cys-Ser (end). Because the catalytic activity of Dm-TrxR is comparable to that of the mammalian selenoenzyme, we introduced the serine residues at the corresponding positions of the recombinant TrxR-X498C and mimicked the redox center of the fruit fly TrxR. However, the catalysis remained as low as the Cys mutant of the selenoenzyme, suggesting that the additional structural features are still required for the tetrapeptide to function as a redox center. MOPAC calculation suggested that the complete motif might involve the hexapeptide sequence, which includes a proline residue, -Pro-X-Ser-Cys-Cys-Ser (end). The proline-containing motif is conserved among other insect TrxRs such as those of honeybee and fruit fly.ほ乳類チオレドキシン還元酵素はＣ末端配列-Gly-Cys-SeCys-Gly（end）の後ろから２番目にセレノシステイン（SeCys）残基を持つ．SeCys をシステインに変換すると酵素の活性は大きく低下するので，SeCys 残基が触媒活性に必須であることが分かる．これに対してキイロショウジョウバエのチオレドキシン還元酵素（Dm-TrxR）のＣ末端配列にはセレンが含まれず，システイン残基の対が２つのセリンに挟まれた配列-Ser-Cys-Cys-Ser (end）を持つ．それでも Dm-TrxR はほ乳類のセレン含有酵素と同程度の触媒能を示す．われわれはヒト肺チオレドキシン還元酵素に Dm-TrxR のＣ末端テトラペプチド配列を導入してその効果を調べた．しかし，酵素活性はまったく上昇せず，Dm-TrxR のＣ末端のテトラペプチド配列-Ser-Cys-Cys-Ser だけでは Cys 残基のチオール基を活性化する効果はなかった．そこで，分子軌道計算 MOPAC を用いて酸化還元機能を担うためのＣ末端配列モチーフを探索した．その結果，テトラペプチドにさらに２つ先のプロリンまでを含めた Pro-X-Ser-Cys-Cys-Ser（end）により初めて酸化還元モチーフとして機能する可能性が示唆された．Pro を含むこの配列モチーフはミツバチや蚊などほかの昆虫の TrxR でも保存されてい