Musashi University

About: Musashi University is a education organization based out in Tokyo, Japan. It is known for research contribution in the topics: Supply chain & Frugivore. The organization has 125 authors who have published 328 publications receiving 3844 citations.

Simulation analysis of supply chain systems with reverse logistics

Abstract: Due to environmental and ecological responsibility, enterprises are trying to reuse, remanufacture and recycle used products to reduce the negative impact on the environment. Reverse logistics is one of essential elements to implement such sustainable supply chain system. This paper proposes methodologies of simulation modeling and analysis of supply chain systems with reverse logistics flows. This paper discusses two types of reverse supply chain: PUSH-type reverse logistics and PULL-type reverse logistics. Generic models are introduced and analysis examples of individual features will be provided.

Reconstruction of multi-millennial summer climate variations in central Japan by integrating tree-ring cellulose oxygen and hydrogen isotope ratios

Abstract: . Oxygen isotope ratios (δ18O) of tree-ring cellulose are a novel proxy of summer hydroclimate in monsoonal Asia. In central Japan, we collected 67 conifer wood samples, mainly Chamaecyparis obtusa, with ages encompassing the past 2,600 yr. The samples were taken from living old trees, excavated archeological wood, old architectural wood, and naturally buried logs. We analyzed stable isotope ratios of oxygen (δ18O) and hydrogen (δ2H) in tree-ring cellulose in these samples without using a pooling method, and constructed a statistically reliable tree-ring cellulose δ18O time-series for the past 2,500 yr. However, there were distinct age trends and level offsets in the δ18O record, and cellulose δ18O values showed a gradual decrease as an individual tree matures. This suggested it is difficult to establish a cellulose δ18O chronology for low-frequency signals by simple averaging of all the δ18O time-series data. However, there were opposite age trends in the cellulose δ2H, and δ2H gradually increased with tree age. There were clear positive correlations in the short periodicity variations between δ18O and δ2H, probably indicating a common climate signal. A comparison of the δ18O and δ2H time-series in individual trees with tree-ring width suggested that the opposite age trends of δ18O and δ2H are caused by temporal changes in the degree of post-photosynthetic isotope exchange with xylem water, accompanied by changes in stem growth rate (growth effect) that are influenced by human activity in the forests of central Japan. Based on the assumptions that cellulose δ18O and δ2H vary positively and negatively with constant proportional coefficients due to climate variations and the growth effect, respectively, we solved simultaneous equations for the climatological and physiological components of variations in tree-ring cellulose δ18O and δ2H in order to remove the age trend (growth effect). This enabled us to evaluate the climatic record from cellulose δ18O variations. The extracted climatological component in the cellulose δ18O for the past 2,600 yr in central Japan was well correlated with numerous instrumental, historical, and paleoclimatological records of past summer climate at various spatial and temporal scales. This indicates that integration of tree-ring cellulose δ18O and δ2H data is a promising method to reconstruct past summer climate variations on annual to millennial time-scales, irrespective of the growth affect. However, analytical and statistical methods need to be improved for further development of this climate proxy.

Preparation and certification of certified reference materials of fish meat and ashed bone for determination of 90 Sr and radiocesium after Fukushima Daiichi Nuclear Power Plant

Abstract: Certified reference materials (CRMs) of the fish meat powder and the fish bone ash for validation of measurement of anthropogenic nuclides (134Cs, 137Cs and 90Sr) related the Fukushima Daiichi nuclear power plant accident were developed using an inter-laboratory comparison. This paper discusses the strategy of development including selection of raw material, the preparation and certification procedures applied for CRM production. In particular, some detailed data are presented for the homogeneity study and inter-laboratory experiment for the certification. The results of inter-laboratory comparison not only to certify CRMs but also showed analytical performance of the anthropogenic nuclides in Japanese laboratories.

Consequences of War: Japan's Demographic Transition and the Marriage Market

Abstract: This study explores the effects of imbalances in the sex ratio, and their impact on intra-household bargaining, on both the quantity and the quality of children. We first present the theoretical model of intra-household bargaining in the presence of conflicting family goals within a couple, and show that male scarcity (a decrease in the male to female sex ratio) induces an increase in the number of children, but a decrease in the quality of children. Second, using the impact of World War II on the sex ratio, as a quasi-natural experiment, we establish empirically that the decrease in the male to female sex ratio in World War II contributed to a lower decline in fertility and child mortality rates in postwar Japan. In particular, the fertility rate would have fallen by an additional 12% and the child mortality rate by an additional 13% between 1948 and 1970, in the absence of the decrease in the sex ratio.

Transforming ‘Everydayness’: Japanese New Left Movements and the Meaning of their Direct Action

Abstract: Many recent studies have discussed the features of Japanese civil society Some of them point out that these have been greatly affected by the legacy of the new left movements, a network of anti-Vietnam War groups, student groups, and young workers’ groups which developed toward the end of the 1960s This article explores the formation and development of the ideas and actions of the Japanese new left movements, examining the discourse of student activists in particular These activists were critical of the conservative consciousness – which they termed ‘everydayness’ – which was a product of the economic boom of that decade, and sought to transform it They were willing to take confrontational direct action against armed police officers on streets and on campus in spite of the risks of arrest and injury I analyse their activism, and the reasons leading to it By exploring the ideas and actions of new left movements, this paper aims to historicize certain features of Japanese civil society