Domain-size control by global feedback in bistable systems

We study domain structures in bistable systems such as the Ginzburg-Landau equation. The size of domains can be controlled by a global negative feedback. The domain-size control is applied for a localized spiral pattern

Analyzing power in elastic scattering of ⁶He from polarized proton target at 71 MeV/nucleon

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Partial Identification and Inference in Duration Models with Endogenous Censoring

This paper studies identification and inference in transformation models with endogenous censoring. Many kinds of duration models, such as the accelerated failure time model, proportional hazard model, and mixed proportional hazard model, can be viewed as transformation models. I allow the censoring of duration outcome to be arbitrarily correlated with observed covariates and unobserved heterogeneity. I impose no parametric restrictions on the transformation function or the distribution function of the unobserved heterogeneity. In this setting, I partially identify the regression parameters and the transformation function, which are characterized by conditional moment inequalities of U-statistics. I provide an inference method for them by constructing an inference approach for the conditional moment inequality models of U-statistics. As an empirical illustration, I apply the proposed inference method to evaluate the effect of heart transplants on patients' survival time using data from the Stanford Heart Transplant Study

Estimation of time-varying average treatment effects using panel data when unobserved fixed effects affect potential outcomes differently

This paper proposes a new approach to estimate the time-varying average treatment effect using panel data to control for unobserved fixed effects. The approach allows identifying the average treatment effect on the entire population, even if the fixed effects affect potential outcomes under treatment and no treatment differently, which can cause heterogeneity in treatment effects among unobserved characteristics. Note that a popularly used standard difference-in-differences approach can only identify the average treatment effect on the treated. Moreover, the proposed approach allows time-varying treatment effects. The approach exploits panel data with a specific structure in which the treatment exposure expands to the entire population over time. I apply the proposed approach to estimate the effect of the introduction of electronic voting technology for the reduction of residual votes in Brazilian elections

Creation of knowledge through exchanges of knowledge: Evidence from Japanese patent data

This study shows evidence for collaborative knowledge creation among individual researchers through direct exchanges of their mutual differentiated knowledge. Using patent application data from Japan, the collaborative output is evaluated according to the quality and novelty of the developed patents, which are measured in terms of forward citations and the order of application within their primary technological category, respectively. Knowledge exchange is shown to raise collaborative productivity more through the extensive margin (i.e., the number of patents developed) in the quality dimension, whereas it does so more through the intensive margin in the novelty dimension (i.e., novelty of each patent)