Stability of axisymmetric chiral skyrmions

We examine topological solitons in a minimal variational model for a chiral magnet, so-called chiral skyrmions. In the regime of large background fields, we prove linear stability of axisymmetric chiral skyrmions under arbitrary perturbations in the energy space, a long-standing open question in physics literature. Moreover, we show strict local minimality of axisymmetric chiral skyrmions and nearby existence of moving soliton solution for the Landau-Lifshitz-Gilbert equation driven by a small spin transfer torque

Well-posedness and stability for a class of fourth-order nonlinear parabolic equations

In this paper we examine well-posedness for a class of fourth-order nonlinear parabolic equation $\partial_t u + (-\Delta)^2 u = \nabla \cdot F(\nabla u)$, where $F$ satisfies a cubic growth conditions. We establish existence and uniqueness of the solution for small initial data in local BMO spaces. In the cubic case $F(\xi) = \pm \lvert \xi \rvert^2 \xi$ we also examine the large time behaivour and stability of global solutions for arbitrary and small initial data in VMO, respectively

Causal Inference with an Interval-censored Exposure

The purpose of this thesis is to use data collected on patients with severe pelvic fractures who received circumferential pelvic compression (CPC) to draw inference about the causal effect of the CPC placement time (since injury) on blood products use. Our approach focused on estimation of the probability of blood product use had all injured patients received CPC at time z after injury. A unique methodological challenge that is addressed is the interval-censoring of time of CPC placement. Our ultimate analysis, which is hampered by limited sample size and information on key confounders, did not find evidence that earlier binder placement reduced the risk of blood product use

A Cross-Cultural Analysis of Sentiment in “COVID-19” Reportage of CCTV News and The New York Times

Drawing support from the artificial intelligence platform of Baidu Cloud and the natural language processing approach, this paper provides an empirically-grounded micro-analysis of Sino-American news discourses on “COVID-19” pandemic in China 2020 by using keyword wordcloud analysis on sentiment expressions, namely the discourses from the websites of CCTV News and The New York Times. The authors analyzed the media’s intended attitudes expressed with sentiment, and found that the attitude of the Chinese people and China’s media towards the epidemic was mostly positive; while New York Times was mostly negative about the epidemic, especially at the peak of the outbreak. Such a difference presents a prevalent manifestation of recognition towards the epidemic led by either government or media institutions while people face uncertainties caused by corona virus, which may further influence the public opinion and attitudes towards the epidemic, which in turn has broader social/political-interactional purposes and public cognitive construction.

On the supply of China's healthcare resources in a decentralized healthcare system

The structure of China’s current governance bears prominent features of fiscal decentralization. The supply of healthcare resources in China has clearly witnessed slower growth in the last two decades during which the fiscal decentralization process has taken place. Using China’s provincial panel data, we examine the determinants of healthcare resource supply while paying particular attention to the role of fiscal decentralization. We find that the supply of healthcare resources is inversely related to the degree of decentralization, which, using spatial econometrics, is attributed to the presence of strategic substitutes in healthcare spending across city governments. These findings have important implications for policy makers in making fiscal arrangements among different government tiers

On the supply of China's healthcare resources in a decentralized healthcare system

The structure of China’s current governance bears prominent features of fiscal decentralization. The supply of healthcare resources in China has clearly witnessed slower growth in the last two decades during which the fiscal decentralization process has taken place. Using China’s provincial panel data, we examine the determinants of healthcare resource supply while paying particular attention to the role of fiscal decentralization. We find that the supply of healthcare resources is inversely related to the degree of decentralization, which, using spatial econometrics, is attributed to the presence of strategic substitutes in healthcare spending across city governments. These findings have important implications for policy makers in making fiscal arrangements among different government tiers