The effect of social distancing on the reach of an epidemic in social networks

How does social distancing affect the reach of an epidemic in social networks? We present Monte Carlo simulation results of a susceptible–infected–removed with social distancing model. The key feature of the model is that individuals are limited in the number of acquaintances that they can interact with, thereby constraining disease transmission to an infectious subnetwork of the original social network. While increased social distancing typically reduces the spread of an infectious disease, the magnitude varies greatly depending on the topology of the network, indicating the need for policies that are network dependent. Our results also reveal the importance of coordinating policies at the ‘global’ level. In particular, the public health benefits from social distancing to a group (e.g. a country) may be completely undone if that group maintains connections with outside groups that are not following suit.

     

Japanese marketing in the post-bubble era

This article analyzes recent changes in marketing practices in Japan against the background of the recession and the high yen rate of the early 1990s. Based on direct observation, press reports, and interviews with experts, the study describes the changing situation in the Japanese market and shows how new opportunities for Western companies are opening up. The longer term implications of the home market changes for Japanese companies' competitiveness abroad are also discussed.     

Panel Asymptotics and Statistical Decision Theory

This paper develops some applications of asymptotic statistical decision theory in econometrics, focusing on settings where the data are organized into groups or cells with heterogeneous parameters. Even if the groups are of different sizes, local asymptotic normality holds under suitable regularity conditions, and this can greatly simplify analysis of different types of econometric problems. We apply these results to the analysis of treatment assignment rules, and to estimators of cell‐specific parameters that employ shrinkage towards parametric models.     

New Dimensions of Financial Liberalization in Japan

This article contrasts the development of Japanese financial institutions over the past 50 years to that of the United States and compares the two countries’ household savings behavior. Although reform and liberalization is driving the Japanese financial sector to become more open and more sophisticated, there are powerful reasons for the Japanese system and Japanese asset-holding behavior to remain divergent from that of the United States. One major factor is that income and wealth in Japan are distributed much more evenly than in the United States. Since wealthy households are more sophisticated and better able to accommodate risk, the concentration of wealth in the United States means that, compared to Japan, there are more high income/high wealth households that are willing to take on risk from equity and bond holdings. In Japan, in contrast, there is a much heavier reliance on bank deposits. Even though financial institutions in the two countries are becoming more similar, the persistent differences in income distribution are likely to lead to persistent differences in asset holding and the composition of capital markets in the two countries. JEL Classification G2, O53     

Simulation Analysis of a Dynamic Reallocation-based Routing Functionality for SAGE Application

A large amount of scientific data is generated through computation and analysis. Also, today’s scientific research necessitates an aggregation of diverse expertise from experts with different backgrounds. Therefore, visualizing and sharing these data among scientists in an intuitive and easy manner is of more importance in scientific collaborative research than ever. We have focused on SAGE, a middleware that realizes a large-scale remote visualization leveraging network streaming technique as a promising building block technology. However, no advanced network control function for efficient use of the network is equipped with SAGE although SAGE relies on a network streaming techniques. Our previous research integrated a functionality that detected network failures avoided such failure by rerouting network flows of SAGE into the functionality. Nonetheless, a network congestion avoidance functionality to adapt a collection of network flows generated by SAGE to the underlying network has not been developed yet. In this paper we explore the feasibility of a reallocation-based dynamic routing functionality for SAGE, with which all network flows on the network are rearranged. For feasibility research, we perform simulation experiments to observe the behavior of the functionality. The evaluation confirms that our proposed functionality works correctly and brings better throughput for each flow.     

Design of randomized experiments to measure social interaction effects

We consider randomized experiments with two levels of randomization for measuring social interaction effects. We examine how the randomization should be carried out to estimate the coefficients of interest most precisely.     

Issues of employment portfolios in Japanese retail businesses

Abstract

The employment portfolio of Japanese retail businesses is composed of regular employees and part-time workers. Even though part-time workers are assigned to significant jobs, their wages tend to be lower than those of regular employees. However, the job satisfaction and motivation of part-time workers are not low. This article aims to consider why part-time workers have a positive attitude toward their jobs. Data were collected from part-time workers of retail businesses (n?=?1133). The specific focus is on two groups: part-time workers compared to regular employees and part-time workers compared to other part-time workers. Results showed that the group compared to part-time workers had more positive job attitude than others. From the point of view of social comparison, the job attitude of part-time workers may differ depending on the choice of who they compare themselves against. The implications of the findings and directions for future research are discussed.     

Cost minimization analysis of beta-blocker at the time of CT imaging for suspected of coronary heart disease in Japan

Objectives:

To conduct a cost-minimization analysis of landiolol for CT diagnosis of coronary heart diseases in patients with tachycardia in Japan.

Methods:

A decision-tree model was constructed to analyze costs from the healthcare payer’s perspective. Drug costs and diagnosis costs, computer tomography coronary angiography (CTCA), and coronary angiography (CAG), are adopted to the model. Landiolol is administered only to slow the heart rate to take CT images appropriately. Since some trials proved that there was no difference between landiolol and placebo in terms of efficacy and safety, this study conducted cost-minimization analysis. Of those suspected of coronary heart diseases, 22.5% are thought to be taking beta-blockers. The success rates for CT scanning for landiolol and placebo, derived from domestic trial data, were 81.4% (96/118, 77.8–84.9%) and 54.2% (64/118, 49.7–58.8%). Patients who failed to take a CT image were thought to take CAG. The healthcare cost was derived from a Japanese fee schedule. Costs of landiolol, CT imaging, and CAG are JPY2634 (USD1?=?JPY100, as of November 20, 2013), JPY38,116, and JPY101,322, respectively. The positive rate for CAG, derived from domestic trial data, was 37.1% (33/89, 32.0–42.2%). Various sensitivity analyses, both univariate and probabilistic ones, were conducted.

Results:

In the base case analysis, expected costs per patient for landiolol and placebo were JPY78,956 and JPY82,232, respectively. In budget impact analysis, 81,062 patients are eligible for landiolol and it can save JPY266million for whole patients. Sensitivity analyses suggested the robustness of the results.

Limitations:

This study did not consider any adverse effects in the decision-tree model. This model was developed especially for measuring the cost-saving effect of landiolol, through decreasing the number of patients who require CAG, due to imaging failure.

Conclusions:

Landiolol for CTCA diagnosis in patients suspected of coronary heart disease with tachycardia is thought to be cost saving.     

美国对外负债的可持续性与国际货币体系的未来

要回归到某种形式的固定汇率制度,需要对国际资本流动进行全面且国际性的管制,乃至各国放弃管理货币制度下行使的金融主权。从经济、政治和政策上考虑,这两种要求都无法实现。欧元、日元、人民币甚至把合成货币(SDR)都考虑在内,也难以想像在可以预测的未来(21世纪中叶为止)能够出现替代美元的货币。美国的对外资产和负债之间有正的投资回报差额,这一差额在长期内将一直存在。只要这种回报差额持续存在,并且对外资产和负债占GDP的比率能够按照一定的速度扩大,那么即便美国的贸易收支逆差占GDP的比率维持在4%左右,其对外纯负债占GDP的比重维持稳定状态的可能性也是很大的。因此,以美元为中心的、由多数主要货币构成的现行浮动汇率制度具有很强的可持续性,以至于完全有可能在今后继续存在。