Three essays on retail globalisation and international trade

Using the empirical context of Korea's retail sector, this thesis brings together three empirical essays that examine the significance of the retail sector in the global economy. The first essay examines how retail market powers influence the impact of tariff cuts on consumer prices in the context of Korea’s tariff reduction since the mid-1980s. Using consumption-item-level consumer price index (CPI) and product-level tariff data with a new matching strategy, we empirically find that tariff cuts incompletely pass through to consumer prices. Guided by a simple theoretical framework based on an oligopolistic competition model with a nested CES demand, this essay considers markups charged by retailers as a new channel by which consumer prices do not fully react to tariff cuts. To identify the retail markup channel, we firstly find that tariff pass-through to consumer prices are deteriorated in regions with greater retail market concentrations. Further, this essay measures retail markups proxied by price-cost margins, and quantifies the degree to which retail markups exacerbate tariff pass-through using a new instrumental variable strategy. The instrument variable estimation reveals that a 10 percentage point increase in retail markups contributes to 1.73-1.96 percent lower tariff pass-through. Our results are robust with estimation based on limited four-year census data by which we account for store-level variations and geographical market heterogeneities in retail markup measure. We also estimate the retail markup channel augmented by spatial autoregressive (SAR) regression model to control for CPI's spatially cross-section dependence, and the results are robust. The second essay aims to answer the question about whether strategic interactions affect FDI (Foreign Direct Investment)'s market entry. From the literature, the answer is less clear as host-country markets are generally considered as being perfectly competitive. Under the imperfectly competitive market, however, even multinational enterprises cannot act in a vacuum. In this essay, we study the strategic aspect of FDI's entry into host-country markets. To study it, we use an empirical context of the Korean discounting retail industry where, as the first and the second biggest firms, a domestic retailer (Emart) competes with a multinational retailer (Tesco) by opening multiple stores across local markets. We empirically show that retail FDI enters host-country markets strategically by reduced-form estimations. Further, we build an entry game-theoretical model in which the strategic interaction is fully incorporated, and estimate the structural parameters of the model. The existence of strategic entry is clearly confirmed by structural estimation results. We also find that asymmetric information between foreign and domestic retailers play a key role in forming FDI's strategic market entry. Lastly, the third essay studies whether multinational enterprises affect domestic firms’ markups. Since Korea liberalised retail FDI in 1996, foreign stores have proliferated over the Korean market whereas average markup of local stores has declined to a large degree. To assess the causal impact of retail FDI on domestic markups, we use the inverse propensity-score weighting regression (IPW) model combined with difference-in-difference (DD) approach. In this essay, we find that multinational retailers have a causal impact on reduction in average local markups. Through the lens of IPW and DD, we also find that the decrease in domestic markups is thoroughly driven by pro-competitive effects through the entry of foreign retailers, but productivity spillover effects induced by multinational retailers are limited. This essay also reveals that Korean large discount stores, of which scales, functions and product assortments are very similar to multinational stores, have no impact on average markups, indicating that only FDI plays a role in decline in markups

Persistent Genital Swelling after Hydrocele Ligation in a Patient Receiving Continuous Ambulatory Peritoneal Dialysis

We report a case of genital swelling in a patient receiving continuous ambulatory peritoneal dialysis. A physical examination did not identify any defect. Ultrasonography revealed a large hydrocele, and surgical repair brought resolution of the genital swelling. Two months later, however, the genital swelling had recurred and was not improved until peritoneal dialysis was replaced by hemodialysis 3 months later

Six-dimensional considerations of Einstein's connection for the first two classes. I. The recurrence relations in 6

Lower dimensional cases of Einstein's connection were already investigated by many authors for n=2,3,4,5. This paper is the first part of the following series of two papers, in which we obtain a surveyable tensorial representation of 6-dimensional Einstein's connection in terms of the unified field tensor, with main emphasis on the derivation of powerful and useful recurrence relations which hold in 6-dimensional Einstein's unified field theory (i.e., 6-g-UFT)

Facile synthesis of nano-Li4 Ti5O12 for high-rate Li-ion battery anodes

One of the most promising anode materials for Li-ion batteries, Li4Ti5O12, has attracted attention because it is a zero-strain Li insertion host having a stable insertion potential. In this study, we suggest two different synthetic processes to prepare Li4Ti5O12 using anatase TiO2 nanoprecursors. TiO2 powders, which have extraordinarily large surface areas of more than 250 m2 g-1, were initially prepared through the urea-forced hydrolysis/precipitation route below 100°C. For the synthesis of Li4Ti5O12, LiOH and Li2CO3 were added to TiO2 solutions prepared in water and ethanol media, respectively. The powders were subsequently dried and calcined at various temperatures. The phase and morphological transitions from TiO2 to Li4Ti5O12 were characterized using X-ray powder diffraction and transmission electron microscopy. The electrochemical performance of nanosized Li4Ti5O12 was evaluated in detail by cyclic voltammetry and galvanostatic cycling. Furthermore, the high-rate performance and long-term cycle stability of Li4Ti5O12 anodes for use in Li-ion batteries were discussed

Generation of a single-cycle pulse using a two-stage compressor and its temporal characterization using a tunnelling ionization method

A single-cycle laser pulse was generated using a two-stage compressor and characterized using a pulse characterization technique based on tunnelling ionization. A 25-fs, 800-nm laser pulse was compressed to 5.5 fs using a gas-filled hollow-core fibre and a set of chirped mirrors. The laser pulse was further compressed, down to the single-cycle limit by propagation through multiple fused-silica plates and another set of chirped mirrors. The two-stage compressor mitigates the development of higher-order dispersion during spectral broadening. Thus, a single-cycle pulse was generated by compensating the second-order dispersion using chirped mirrors. The duration of the single-cycle pulse was 2.5 fs, while its transform-limited duration was 2.2 fs. A continuum extreme ultraviolet spectrum was obtained through high-harmonic generation without applying any temporal gating technique. The continuum spectrum was shown to have a strong dependence on the carrier-envelope phase of the laser pulse, confirming the generation of a single-cycle pulse. © 2019, The Author(s

Effects of Berberine and Hwangryunhaedok-Tang on Oral Bioavailability and Pharmacokinetics of Ciprofloxacin in Rats

Hwangryunhaedok-Tang (HR) and berberine-containing single herbs are used to treat bacterial infection and inflammatory diseases in eastern Asia. The combination of berberine-containing herbal medicines and ciprofloxacin can be an excellent antibacterial chemotherapy against multidrug resistance bacteria. To evaluate the pretreatment effect of berberine and HR, vehicle, berberine (25 and 50 mg/kg/day), and HR (1.4 g/kg/day) were daily administered to rats for five consecutive days. On day 6, ciprofloxacin was administered (10 mg/kg, i.v. and 20 mg/kg, p.o.) to rats. To assess cotreatment effect of berberine and ciprofloxacin, berberine (50 mg/kg) and ciprofloxacin (20 mg/kg) were coadministered by single oral gavage. Pharmacokinetic data were estimated by noncompartmental model. Compared with ciprofloxacin alone (control group), coadministration of berberine (50 mg/kg) and ciprofloxacin significantly decreased Cmax of ciprofloxacin (P<0.05). In addition, the pretreatment of berberine (50 mg/kg/day) and HR (1.4 g/kg/day) significantly decreased Cmax and AUC0→∞, compared with control group (P<0.05). The oral bioavailability of ciprofloxacin was reduced by cotreatment of berberine and pretreatment of berberine and HR. Our results suggest that the expression of P-glycoprotein and organic anion and/or organic cation transporters (OAT/OCT) could take a role in reduced oral bioavailability of ciprofloxacin by berberine and HR

Carriage of Cytochrome 2C19 Polymorphism Is Associated With Risk of High Post-Treatment Platelet Reactivity on High Maintenance-Dose Clopidogrel of 150 mg/day Results of the ACCEL-DOUBLE (Accelerated Platelet Inhibition by a Double Dose of Clopidogrel According to Gene Polymorphism) Study

ObjectivesThis study sought to determine the impact of gene polymorphisms on platelet reactivity (PR) after clopidogrel 150 mg/day in patients treated with percutaneous coronary intervention (PCI).BackgroundAlthough high maintenance-dose (MD) clopidogrel reduces PR, it is unknown whether gene polymorphisms are related with the risk of high post-treatment PR (HPPR) after high-MD clopidogrel.MethodsWe included mostly patients receiving high-MD clopidogrel after PCI from previously registered Gyeongsang National University Hospital data. A total of 126 PCI-treated patients receiving high-MD clopidogrel were enrolled. Platelet reactivity was assessed with conventional aggregometry and VerifyNow (Accumetrics Inc., San Diego, California) after receiving clopidogrel 150 mg/day for at least 1 month. CYP3A5, CYP2C19, and ABCB1 genotyping was performed. We defined HPPR as 5 μmol/l adenosine diphosphate (ADP)–induced maximal PR (PRmax) >50%.ResultsCYP3A5 and ABCB1 polymorphisms did not influence PR. Carriers of CYP2C19 variant (*2 or *3) (n = 80) had significantly higher 5 and 20 μmol/l ADP-induced PRmax than did noncarriers (n = 46) (40.7 ± 16.8% vs. 30.3 ± 12.6%, p < 0.001; 54.2 ± 16.2% vs. 40.5 ± 15.8%, p < 0.001, respectively). Late PR and VerifyNow results indicated consistently greater measures in carriers versus noncarriers of CYP2C19 variant. All platelet measures proportionally increased according to the number of CYP2C19 variant alleles. Twenty-seven (21.4%) patients met the criteria for HPPR. Prevalence of HPPR was 8.7%, 21.7%, and 50.0% in carriers of 0, 1, and 2 CYP2C19 variant alleles, respectively (p < 0.001). By multivariate analysis, carriage of CYP2C19 variant was a significant predictor of HPPR (odds ratio: 5.525, 95% confidence interval: 1.333 to 23.256, p = 0.018).ConclusionsAmong PCI-treated patients receiving high-MD clopidogrel, carriage of CYP2C19 variant relates to increased PR and predicts risk of HPPR. (Adjunctive Cilostazol Versus High Maintenance-dose ClopidogrEL in Acute Myocardial Infarction [AMI] Patients According to CYP2C19 Polymorphism [ACCELAMI2C19]; NCT00915733; and Comparison of Platelet Inhibition With Adjunctive Cilostazol Versus High Maintenance-Dose Clopidogrel According to Hepatic Cytochrome 2C19 Allele (CYP2C19) Polymorphism [ACCEL2C19]; NCT00891670)

Subchronic oral toxicity of silver nanoparticles

<p>Abstract</p> <p>Background</p> <p>The antibacterial effect of silver nanoparticles has resulted in their extensive application in health, electronic, consumer, medicinal, pesticide, and home products; however, silver nanoparticles remain a controversial area of research with respect to their toxicity in biological and ecological systems.</p> <p>Results</p> <p>This study tested the oral toxicity of silver nanoparticles (56 nm) over a period of 13 weeks (90 days) in F344 rats following Organization for Economic Cooperation and Development (OECD) test guideline 408 and Good Laboratory Practices (GLP). Five-week-old rats, weighing about 99 g for the males and 92 g for the females, were divided into four 4 groups (10 rats in each group): vehicle control, low-dose (30 mg/kg), middle-dose (125 mg/kg), and high-dose (500 mg/kg). After 90 days of exposure, clinical chemistry, hematology, histopathology, and silver distribution were studied. There was a significant decrease (P < 0.05) in the body weight of male rats after 4 weeks of exposure, although there were no significant changes in food or water consumption during the study period. Significant dose-dependent changes were found in alkaline phosphatase and cholesterol for the male and female rats, indicating that exposure to more than 125 mg/kg of silver nanoparticles may result in slight liver damage. Histopathologic examination revealed a higher incidence of bile-duct hyperplasia, with or without necrosis, fibrosis, and/or pigmentation, in treated animals. There was also a dose-dependent accumulation of silver in all tissues examined. A gender-related difference in the accumulation of silver was noted in the kidneys, with a twofold increase in female kidneys compared to male kidneys.</p> <p>Conclusions</p> <p>The target organ for the silver nanoparticles was found to be the liver in both the male and female rats. A NOAEL (no observable adverse effect level) of 30 mg/kg and LOAEL (lowest observable adverse effect level) of 125 mg/kg are suggested from the present study.</p