An evolving network model of credit risk contagion in the financial market

This paper introduces an evolving network model of credit risk contagion containing the average fitness of credit risk contagion, the risk aversion sentiments, and the ability of resist risk of credit risk holders. We discuss the effects of the aforementioned factors on credit risk contagion in the financial market through a series of theoretical analysis and numerical simulations. We find that, on one hand, the infected path distribution of the network gradually increases with the increase in the average fitness of credit risk contagion and the risk aversion sentiments of nodes, but gradually decreases with the increase in the ability to resist risk of nodes. On the other hand, the average fitness of credit risk contagion and the risk aversion sentiments of nodes increase the average clustering coefficient of nodes, whereas the ability to resist risk of nodes decreases this coefficient. Moreover, network size also decreases the average clustering coefficient. First published online: 29 Feb 201

Assessment of potential dietary toxicity and arsenic accumulation in two contrasting rice genotypes : effect of soil amendments

High concentration of arsenic (As) in rice is a serious problem worldwide. Pot experiments were conducted to assess the potential dietary toxicity of arsenic and effect of various soil amendments on arsenic accumulation in rice grains. Two basmati rice genotypes were used to conduct pot experiments using various levels of arsenic (10, 25, 50 and 100 mg kg-1 29 soil). In addition, plants were exposed to soil collected from a well documented arsenic contaminated site. Contrasting results for growth, yield and grain arsenic concentration were obtained for basmati-385 (Bas-385), exhibiting tolerance (56% yield improvement at 10 mg As kg-1 32 ), while genotype BR-1 showed 18% yield decline under same conditions. Furthermore, application ofsoil amendments such as iron (Fe), phosphate (PO4) and farmyard manure (FYM) at 50 mg kg-1,80 kg ha-1 and 10 t ha-1, respectively improved the plant height and biomass in both genotypes. Accumulation of arsenic in rice grain followed a linear trend in BR-1 whereas a parabolic relationship was observed in Bas-385. Both genotypes exhibited a positive response to iron sulfate amendment with significant reduction in grain arsenic concentrations. Regression analysis gave soil arsenic threshold values of 12 mg kg-1 in Bas-385 and 10 mg kg-1 39 in BR-1 for potential dietary toxicity. This study suggests that genotype Bas-385 can be used for safe rice production in areas with soil arsenic contamination up to 12 mg kg-1 41 and that appropriate dose of iron sulfate for soil amendment can be used effectively to reduce translocation of arsenic to rice grai

Deciphering the functional importance of comammox vs. canonical ammonia oxidisers in nitrification and N2O emissions in acidic agricultural soils

Acknowledgments This work was jointly supported by grants from the National Key Research and Development Program of China (2018YFD0800202), the National Key Research and Development Program of China (2017YFD0200707 & 2017YFD0200102), the Fundamental Research Funds for the Central Universities (226-2023-00077) and Zhejiang University-Julong Ecological Environment R&D Centre (2019-KYY-514106-0006).Peer reviewe

Complex Dynamics of Credit Risk Contagion with Time-Delay and Correlated Noises

The stochastic time-delayed system of credit risk contagion driven by correlated Gaussian white noises is investigated. Novikov’s theorem, the time-delay approximation, the path-integral approach, and first-order perturbation theory are used to derive time-delayed Fokker-Planck model and the stationary probability distribution function of the dynamical system of credit risk contagion in the financial market. Using the method of numerical simulation, the Hopf bifurcation and chaotic behaviors of credit risk contagion are analyzed when time-delay and nonlinear resistance coefficient are varied and the effects of time-delay, nonlinear resistance and the intensity and the correlated degree of correlated Gaussian white noises on the stationary probability distribution of credit risk contagion are investigated. It is found that, as the infectious scale of credit risk and the wavy frequency of credit risk contagion are increased, the stability of the system of credit risk contagion is reduced, the dynamical system of credit risk contagion gives rise to chaotic phenomena, and the chaotic area increases gradually with the increase in time-delay. The nonlinear resistance only influences the infectious scale and range of credit risk, which is reduced when the nonlinear resistance coefficient increases. In addition, the curve of the stationary probability distribution is monotone decreasing with the increase in parameters value of time-delay, nonlinear resistance, and the intensity and the correlated degree of correlated Gaussian white noises

An Entropy Model of Credit Risk Contagion in the CRT Market

This paper reports the effect of the change in the credit status of debtors on investors as a result of the banks’ transferring of credit risk to investors in the credit risk transfer (CRT) market. Thus, an entropy spatial model is introduced, in which the spatial distance and nonlinear coupling between the banks and the investors, the transfer ability of credit risk of banks, and investor appetite for risk in the CRT network are considered. The contagion effects of the credit default of debtor on the default rates of investors in the CRT market are investigated using numerical simulation and sensitivity analysis

THIN-WALLED FOUR-POINT CONTACT BALL BEARING CONTACT FINITE ELEMENT ANALYSIS

Based on the ANSYS finite element software,the method of dividing the contact area of the four point contact ball bearing is proposed. Establish a uniform thin four point contact ball bearing 1/2 single rolling and ring and the bearing finite element model. Calculation and analysis of the grid cell size on contact characteristics of four point contact ball bearing accuracy influence and solve the bearing finite element model in the static radial force load distribution rules and obtained the thin-walled four point contact ball bearing,the more precise the elliptic contact area shape and four point connected contact state. Research shows that: for the calculation of the contact characteristics and the size of mesh generation approximate to 50 percent of the semi minor axis of the contact ellipse can get more precise results,for thin walled four point contact ball bearings,ball and the inner and outer rolling contact should force,the equivalent force and contact deformation and radial load is nonlinear ascending relationship,contact force and load distribution of the calculated results with the Hertz contact theory should be calculated values are in good agreement. The calculation results are more accurate to simulate the contact characteristics and load distribution of the thin wall four point contact ball bearing

An Entropy Model of Credit Risk Contagion in the CRT Market

This paper reports the effect of the change in the credit status of debtors on investors as a result of the banks' transferring of credit risk to investors in the credit risk transfer (CRT) market. Thus, an entropy spatial model is introduced, in which the spatial distance and nonlinear coupling between the banks and the investors, the transfer ability of credit risk of banks, and investor appetite for risk in the CRT network are considered. The contagion effects of the credit default of debtor on the default rates of investors in the CRT market are investigated using numerical simulation and sensitivity analysis

Mechanical Characteristics of Ballast Bed under Dynamic Stabilization Operation Based on Discrete Element and Experimental Approaches

To study the mechanical characteristics of ballasted bed under dynamic stability, a three-dimensional discrete element model of ballasted bed with 1000 mm × 700 mm × 550 mm is established based on the discrete element method. Meanwhile, a simulation test bench with the same size is built for simulation analysis and experimental research. The variation law and trend of settlement, lateral resistance, and compactness of ballasted bed under different excitation frequencies are analyzed comprehensively. The results show that when the excitation frequency is constant, the lateral resistance of sleeper, the settlement of sleeper, and the compactness of track bed under sleeper increase first and then tend to be stable. With the increase in horizontal excitation frequency, lateral resistance of ballast bed, sleeper settlement, and compactness first increase and then decrease after stable operation. The values of these parameters are maximized when the excitation frequency is 36 Hz which is the relative optimal horizontal excitation frequency of this model