Banking reforms, performance and risk in China

We investigate the impact of the banking reform started from 2005 on ownership structures in China on commercial banks’ profitability, efficiency and risk over the period 2000–2012, providing comprehensive evidence on the impact of banking reform in China. We find that banks on average tend to have higher profitability, lower risk and lower efficiency after the reforms, and the results are robust with our difference-in-difference approach. Our results also show that the Big 5 state-owned banks (SOCB) underperform banks with other types of ownership when risk is measured by non-performing loans (NPLs) over the entire study period but tend to have fewer NPLs than other banks during the post-reform period. Our results provide some supporting evidence on the ongoing banking reforms in China, suggesting that attracting strategic foreign investors and listing SOCBs on stock exchanges appear to be effective ways to help SOCBs deal with the problem of NPLs and manage their risk

Evaluating Gilbert Damping in Magnetic Insulators from First Principles

Magnetic damping has a significant impact on the performance of various magnetic and spintronic devices, making it a long-standing focus of research. The strength of magnetic damping is usually quantified by the Gilbert damping constant in the Landau-Lifshitz-Gilbert equation. Here we propose a first-principles based approach to evaluate the Gilbert damping constant contributed by spin-lattice coupling in magnetic insulators. The approach involves effective Hamiltonian models and spin-lattice dynamics simulations. As a case study, we applied our method to Y$_3$Fe$_5$O$_{12}$, MnFe$_2$O$_4$ and Cr$_2$O$_3$. Their damping constants were calculated to be $0.8\times10^{-4}$, $0.2\times10^{-4}$, $2.2\times 10^{-4}$, respectively at a low temperature. The results for Y$_3$Fe$_5$O$_{12}$ and Cr$_2$O$_3$ are in good agreement with experimental measurements, while the discrepancy in MnFe$_2$O$_4$ can be attributed to the inhomogeneity and small band gap in real samples. The stronger damping observed in Cr$_2$O$_3$, compared to Y$_3$Fe$_5$O$_{12}$, essentially results from its stronger spin-lattice coupling. In addition, we confirmed a proportional relationship between damping constants and the temperature difference of subsystems, which had been reported in previous studies. These successful applications suggest that our approach serves as a promising candidate for estimating the Gilbert damping constant in magnetic insulators.Comment: 14 pages, 11 figure

Why do banks issue equity?

US banks maintain significantly higher capital levels than required by regulatory authorities. In addition to complying with capital regulations, this paper investigates the motivations behind banks' decisions to issue equity. We find that banks use seasoned equity offerings (SEOs) to expand their assets. Our findings indicate that banks conducting SEOs experience not only an increase in their capital ratios but also in deposits and assets in the years following the SEO, compared to the other banks. The newly raised funds are primarily invested in for-sale loans and other loans. There is an overall increase in risk and a decrease in market-to-book value during the post-SEO period. Our results are not driven by changes in deposit supply before or after the bank's SEO and remain robust when tested with alternative placebo-matched samples. Taken together, our findings suggest that banks engage in risk-taking behaviors, and highlight the importance of regulating the size of banks

Why do banks issue equity?

US banks maintain significantly higher capital levels than required by regulatory authorities. In addition to complying with capital regulations, this paper investigates the motivations behind banks' decisions to issue equity. We find that banks use seasoned equity offerings (SEOs) to expand their assets. Our findings indicate that banks conducting SEOs experience not only an increase in their capital ratios but also in deposits and assets in the years following the SEO, compared to the other banks. The newly raised funds are primarily invested in for-sale loans and other loans. There is an overall increase in risk and a decrease in market-to-book value during the post-SEO period. Our results are not driven by changes in deposit supply before or after the bank's SEO and remain robust when tested with alternative placebo-matched samples. Taken together, our findings suggest that banks engage in risk-taking behaviors, and highlight the importance of regulating the size of banks

Characterization and density functional theory study of the antioxidant activity of quercetin and its sugar-containing analogues

Inhibition of free radicals using quercetin, hyperin and rutin is examined to determine their antioxidant effects and the structure-activity relationships of flavonoids. Two species of the free radicals are used, including hydroxyl radical (.OH) and superoxide anion radical (O-2(-)). Density functional theory calculations under the level of B3LYP/6-311G (d) have been utilized to explore the structure, molecular properties and antioxidant abilities of the three flavonoids. Bond dissociation enthalpy (BDE) and frontier molecular orbital energy gap are investigated. They are compared with the experiment results assayed by the spectrophotometric. All of the flavonoids show a high activity on inhibiting OH and O-2(-) radicals. Scavenging activity determined by half maximal inhibitory concentration (IC50) values of the three flavonoids decreases in the order: quercetin > hyperin > rutin. The calculations show that quercetin owns the lowest BDE values, which agree well with the experimental results of antioxidant activity determined by IC50 values

General time-reversal equivariant neural network potential for magnetic materials

This study introduces time-reversal E(3)-equivariant neural network and SpinGNN++ framework for constructing a comprehensive interatomic potential for magnetic systems, encompassing spin-orbit coupling and noncollinear magnetic moments. SpinGNN++ integrates multitask spin equivariant neural network with explicit spin-lattice terms, including Heisenberg, Dzyaloshinskii-Moriya, Kitaev, single-ion anisotropy, and biquadratic interactions, and employs time-reversal equivariant neural network to learn high-order spin-lattice interactions using time-reversal E(3)-equivariant convolutions. To validate SpinGNN++, a complex magnetic model dataset is introduced as a benchmark and employed to demonstrate its capabilities. SpinGNN++ provides accurate descriptions of the complex spin-lattice coupling in monolayer CrI$_3$ and CrTe$_2$, achieving sub-meV errors. Importantly, it facilitates large-scale parallel spin-lattice dynamics, thereby enabling the exploration of associated properties, including the magnetic ground state and phase transition. Remarkably, SpinGNN++ identifies a new ferrimagnetic state as the ground magnetic state for monolayer CrTe2, thereby enriching its phase diagram and providing deeper insights into the distinct magnetic signals observed in various experiments.Comment: 27 pages,6 figures and 3 table