ESSAYS ON CAPITAL FLOWS IN DEVELOPING COUNTRIES

In the first chapter, I develop a quantitative small-open-economy model to assess the optimal pace of foreign reserve accumulation by developing countries. The model features endogenous growth with foreign direct investment (FDI) entry and sudden stops of capital inflows to incorporate benefits of reserve accumulation. Reserve accumulation depreciates the real exchange rate and attracts FDI, which endogenously promotes productivity growth. When a sudden stop happens, the government uses accumulated reserve to prevent a severe economic downturn. The calibrated model shows that two factors are the key determinants of the optimal pace of reserve accumulation: the elasticity of the foreign borrowing spread with respect to debt, and the entry cost for FDI. The model suggests that these two factors can explain a substantial amount of the cross-country variation in the observed pace of reserve accumulation. The second chapter is a joint work with Felipe Saffie. In this chapter, we develop a small-open-economy model with endogenous firm and trade dynamics. Aggregate productivity of the economy increases through new firm entry and incumbent firms' innovation. Firms invest in two types of innovation: innovation to acquire new product lines, and innovation to start exporting their products. These innovation activities determine the extensive margins of imports and exports. The economy is also subject to sudden stops of capital inflows. The model can capture some of the empirical regularities of firm and trade dynamics during sudden stops: firms' innovation drops sharply, which causes a persistent decline in productivity and output; imports of goods decline substantially, while exports are almost unaffected; profits for exports increase due to a large real depreciation and lower production cost; the extensive margin of exports gradually expands after sudden stops. The model provides a tractable framework to study optimal capital policies in the context of endogenous firm and trade dynamics

An Awareness of Japanese Crew in the EMS Helicopter on Organizational Management

Abstract. Kushiro city general hospital and Kojinkai Memorial Hospital started EMS Project on 5 October 2009. It had worked 14 times on 26 November, and save a lot of lives. The EMS helicopter plays an important role of regional differences in medication. The EMS operates three institutions -an Aviation Organization, a Medical Organization and a Fire Organization. However, the cooperation of labor doesn't happen in their division of labors. It does not make divide the work. This is because the EMS does not divide work and responsibilities clearly one solution is to have a common field of responsibility across the 3 organization order to improve cooperation. Since this study analyzes the EMS organization from the knowledge creation point of view. This paper is based on a month-long research study at hospital waiting rooms

Somatic polyploidization and characterization of induced polyploids of Dioscorea rotundata and Dioscorea cayenensis

Genetic improvement of major food yams is constrained by a number of factors, such as the scarcity of flowers and lack of synchronization between male and female flowering. Consequently, somaclonal variation including somatic polyploidization has been considered as a useful tool in yam breeding. Somatic polyploidization and its effect on phenotypic traits of Dioscorea species such as D. alata, D. japonica and D. zingiberensis has been reported; however, optimization of this method in two major yam species, D. rotundata and D. cayenensis, is yet to be achieved and the effect of polyploidization on phenotypic traits of this species yet to be elucidated. In the present study, a high rate of somaclonal polyploid variation was successfully achieved by in vitro colchicine treatment of D. rotundata and D. cayenensis. In most cases, except TDc 3704, the highest rate of polyploid induction appeared after 0.1% colchicine treatment. However, in triploid yellow yam accessions the induction rate was relatively low. Tetraploid variants of D. rotundata tended to display somewhat rounder leaves than their diploid parents. The size and shape of D. rotundata stoma were also affected by levels of ploidy, with tetraploid variants exhibiting larger stomata at alower density compared to their diploid parents. The efficient method of in vitro polyploidy induction reported here is therefore a highly useful tool for obtaining polyploid variants for use as genetic resources in D. rotundata breeding.Keywords: Leaf, nodal segment culture, ploidy level, somaclonal variation, stoma, white guinea yam, yellow Guinea ya

ラット肝腫瘍モデルにおける化学療法の早期効果判定に有用なダイナミック造影超音波のパラメータについて

Objectives: The objective of the study is to determine a parameter on the time-intensity curve (TIC) of dynamic contrast-enhanced ultrasonography (DCE-US) that best correlates with tumor growth and to evaluate whether the parameter could correlate with the early response to irinotecan in a rat liver tumor model. Material and Methods: Twenty rats with tumors were evaluated (control: Saline, n = 6; treatment: Irinotecan, n = 14) regarding four parameters from TIC: Peak intensity (PI), k value, slope (PI × k), and time to peak (TTP). Relative changes in maximum tumor diameter between day 0 and 10, and parameters in the first 3 days were evaluated. The Mann-Whitney U-test was used to compare differences in tumor size and other parameters. Pearson’s correlation coefficients (r) between tumor size and parameters in the control group were calculated. In the treatment group, relative changes of parameters in the first 3 days were compared between responder and non-responder (<20% and ≥20% increase in size on day 10, respectively). Results: PI, k value, PI × k, and TTP significantly correlated with tumor growth (r = 0.513, 0.911, 0.665, and 0.741, respectively). The mean RC in k value among responders (n = 6) was significantly lower than non-responders (n = 8) (mean k value, 4.96 vs. 72.5; P = 0.003). Conclusion: Parameters of DCE-US could be a useful parameter for identifying early response to irinotecan.博士（医学）・甲第879号・令和5年3月15

ガク カンセツショウ カンジャ ニオケル MR ガゾウ ショケン ト リンショウ ショケン ノ ヒカク ケントウ

Two hundred eighteen (28.4%) of 768 patients with temporomandibular disorders (TMD), who visited the Clinic for Temporomandibular Disorders, Tokushima University Medical and Dental Hospital during the period of January 2006 through December 2007, were examined using magnetic resonance (MR) imaging. The present study assessed clinico-statistically the correlation between MR images and the clinical findings of 157 patients with complete registered data in our TMD reporting system. The following findings were obtained: 1. MR imaging showed anterior disk displacement in 125 joints (67.9%), rotational disk displacement in 45 joints (24.5%), and sideways disk displacement in 13 joints (7.1%). 2. Joint effusion (JE) was found in 42.7% of 157 patients; 48.0% in females and 23.5% in males. In addition, anterior or rotational disk displacement was observed in 97% of patients with JE. Furthermore, condyle bone change was significantly higher in joints with than without JE. 3. The appearance of JE was significantly higher on the symptomatic side than the asymptomatic side, but tenderness of the temporomandibular joint (TMJ) area or the value of the visual analog scale (VAS) regarding pain and problems in daily life was not related to the presence of JE

Disorganization of Semantic Brain Networks in Schizophrenia Revealed by fMRI

OBJECTIVES: Schizophrenia is a mental illness that presents with thought disorders including delusions and disorganized speech. Thought disorders have been regarded as a consequence of the loosening of associations between semantic concepts since the term "schizophrenia" was first coined by Bleuler. However, a mechanistic account of this cardinal disturbance in terms of functional dysconnection has been lacking. To evaluate how aberrant semantic connections are expressed through brain activity, we characterized large-scale network structures of concept representations using functional magnetic resonance imaging (fMRI). STUDY DESIGN: We quantified various concept representations in patients' brains from fMRI activity evoked by movie scenes using encoding modeling. We then constructed semantic brain networks by evaluating the similarity of these semantic representations and conducted graph theory-based network analyses. STUDY RESULTS: Neurotypical networks had small-world properties similar to those of natural languages, suggesting small-worldness as a universal property in semantic knowledge networks. Conversely, small-worldness was significantly reduced in networks of schizophrenia patients and was correlated with psychological measures of delusions. Patients' semantic networks were partitioned into more distinct categories and had more random within-category structures than those of controls. CONCLUSIONS: The differences in conceptual representations manifest altered semantic clustering and associative intrusions that underlie thought disorders. This is the first study to provide pathophysiological evidence for the loosening of associations as reflected in randomization of semantic networks in schizophrenia. Our method provides a promising approach for understanding the neural basis of altered or creative inner experiences of individuals with mental illness or exceptional abilities, respectively

Metabolic analysis of radioresistant medulloblastoma stem-like clones and potential therapeutic targets

Medulloblastoma is a fatal brain tumor in children, primarily due to the presence of treatment-resistant medulloblastoma stem cells. The energy metabolic pathway is a potential target of cancer therapy because it is often different between cancer cells and normal cells. However, the metabolic properties of medulloblastoma stem cells, and whether specific metabolic pathways are essential for sustaining their stem cell-like phenotype and radioresistance, remain unclear. We have established radioresistant medulloblastoma stem-like clones (rMSLCs) by irradiation of the human medulloblastoma cell line ONS-76. Here, we assessed reactive oxygen species (ROS) production, mitochondria function, oxygen consumption rate (OCR), energy state, and metabolites of glycolysis and tricarboxylic acid cycle in rMSLCs and parental cells. rMSLCs showed higher lactate production and lower oxygen consumption rate than parental cells. Additionally, rMSLCs had low mitochondria mass, low endogenous ROS production, and existed in a low-energy state. Treatment with the metabolic modifier dichloroacetate (DCA) resulted in mitochondria dysfunction, glycolysis inhibition, elongated mitochondria morphology, and increased ROS production. DCA also increased radiosensitivity by suppression of the DNA repair capacity through nuclear oxidization and accelerated the generation of acetyl CoA to compensate for the lack of ATP. Moreover, treatment with DCA decreased cancer stem cell-like characters (e.g., CD133 positivity and sphere-forming ability) in rMSLCs. Together, our findings provide insights into the specific metabolism of rMSLCs and illuminate potential metabolic targets that might be exploited for therapeutic benefit in medulloblastoma

Survey of Period Variations of Superhumps in SU UMa-Type Dwarf Novae. II: The Second Year (2009-2010)

As an extension of the project in Kato et al. (2009, arXiv:0905.1757), we collected times of superhump maxima for 61 SU UMa-type dwarf novae mainly observed during the 2009-2010 season. The newly obtained data confirmed the basic findings reported in Kato et al. (2009): the presence of stages A-C, as well as the predominance of positive period derivatives during stage B in systems with superhump periods shorter than 0.07 d. There was a systematic difference in period derivatives for systems with superhump periods longer than 0.075 d between this study and Kato et al. (2009). We suggest that this difference is possibly caused by the relative lack of frequently outbursting SU UMa-type dwarf novae in this period regime in the present study. We recorded a strong beat phenomenon during the 2009 superoutburst of IY UMa. The close correlation between the beat period and superhump period suggests that the changing angular velocity of the apsidal motion of the elliptical disk is responsible for the variation of superhump periods. We also described three new WZ Sge-type objects with established early superhumps and one with likely early superhumps. We also suggest that two systems, VX For and EL UMa, are WZ Sge-type dwarf novae with multiple rebrightenings. The O-C variation in OT J213806.6+261957 suggests that the frequent absence of rebrightenings in very short-Porb objects can be a result of sustained superoutburst plateau at the epoch when usual SU UMa-type dwarf novae return to quiescence preceding a rebrightening. We also present a formulation for a variety of Bayesian extension to traditional period analyses.Comment: 63 pages, 77 figures, 1 appendix, Accepted for publication in PASJ, data correctio

Survey of Period Variations of Superhumps in SU UMa-Type Dwarf Novae. VIII: The Eighth Year (2015-2016)

Continuing the project described by Kato et al. (2009, arXiv:0905.1757), we collected times of superhump maxima for 128 SU UMa-type dwarf novae observed mainly during the 2015-2016 season and characterized these objects. The data have improved the distribution of orbital periods, the relation between the orbital period and the variation of superhumps, the relation between period variations and the rebrightening type in WZ Sge-type objects. Coupled with new measurements of mass ratios using growing stages of superhumps, we now have a clearer and statistically greatly improved evolutionary path near the terminal stage of evolution of cataclysmic variables. Three objects (V452 Cas, KK Tel, ASASSN-15cl) appear to have slowly growing superhumps, which is proposed to reflect the slow growth of the 3:1 resonance near the stability border. ASASSN-15sl, ASASSN-15ux, SDSS J074859.55+312512.6 and CRTS J200331.3-284941 are newly identified eclipsing SU UMa-type (or WZ Sge-type) dwarf novae. ASASSN-15cy has a short (~0.050 d) superhump period and appears to belong to EI Psc-type objects with compact secondaries having an evolved core. ASASSN-15gn, ASASSN-15hn, ASASSN-15kh and ASASSN-16bu are candidate period bouncers with superhump periods longer than 0.06 d. We have newly obtained superhump periods for 79 objects and 13 orbital periods, including periods from early superhumps. In order that the future observations will be more astrophysically beneficial and rewarding to observers, we propose guidelines how to organize observations of various superoutbursts.Comment: 123 pages, 162 figures, 119 tables, accepted for publication in PASJ (including supplementary information