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Highlights • Combined causal forest algorithm and complex network method. • Considered heterogeneous treatment effects of COVID-19 on industries. • Advised on industrial support policies during COVID-19 pandemic. • Compared types of industrial risk contagion before and after the pandemic., We use the cutting-edge causal forest algorithm to analyze the heterogeneous treatment effects of the COVID-19 outbreak on China's industry indexes. The variable importance index is used with the causal forest and complex network methods to analyze the characteristics of industrial relations and the types of industry risk contagion before and after the COVID-19 outbreak. The results show that the heterogeneity of industries was significantly weakened during the COVID-19 outbreak. In addition, the COVID-19 outbreak changed the original structure of the industry-related network, which shifted to a star network structure with leisure services at the core. It also changed the type of risk contagion between industries, from the original middleman risk type to the input risk type.

In this paper, we consider the problem of optimal dividend payout and equity issuance for a company whose liquid asset is modeled by the dual of classical risk model with diffusion. We assume that there exist both proportional and fixed transaction costs when issuing new equity. Our objective is to maximize the expected cumulative present value of the dividend payout minus the equity issuance until the time of bankruptcy, which is defined as the first time when the company’s capital reserve falls below zero. The solution to the mixed impulse-singular control problem relies on two auxiliary subproblems: one is the classical dividend problem without equity issuance, and the other one assumes that the company never goes bankrupt by equity issuance. We first provide closed-form expressions of the value functions and the optimal strategies for both auxiliary subproblems. We then identify the solution to the original problem with either of the auxiliary problems. Our results show that the optimal strategy should either allow for bankruptcy or keep the company’s reserve above zero by issuing new equity, depending on the model’s parameters. We also present some economic interpretations and sensitivity analysis for our results by theoretical analysis and numerical examples.

Purpose– China's resource allocation mechanism in education has become an important factor in determining residential access to educational resources. The purpose of this paper is to analyze the impacts made by the individual natures of buyers, the external environment, as well as the characteristics of residential properties on the willingness price of buyers. The study's aim is to lay theoretical foundations for the determination of problems related with the matters under consideration.Design/methodology/approach– Using the panel data of 54 districts and counties in Beijing, Shanghai, Guangzhou and Shenzhen, the study unifies macro factors and micro factors in a model for empirical analysis.Findings– Basic education resources can affect housing prices via the “capitalization of education.” The degree of those educational resources’ influence on willingness price changes according to personal income levels, standards of living, housing price fluctuations, the convenience of the residential area and the degrees of urbanization in a district. The greater the buyer's income and standard of living is, the higher is their willingness price. Buyers in urbanized areas prefer increases in educational resources. Increased educational resources increase the values of residential downtown areas. In developed areas with private educational facilities, the role of educational resources in influencing property prices is relatively small.Originality/value– This paper uses data concerning the consumption and investment of residential properties to build a theoretical model for the willingness price of buyers. It unifies macro factors and micro factors in a single model and presents new results about basic education resources and the willingness price of buyers under different conditions.

The formation of 3D fused 10-membered “bracelet” frameworks derived from the alkyl-substituted curcurbit[5]urils (SQ[5]s), 1,2,4-hexamethylcucurbit[5]uril (1,2,4-HMeQ[5]), and pentacyclopentanocucurbit[5]uril (PCyHQ[5]) and K+ ions is described. These remarkable catenated structures feature trigonal-planar branching units involving three SQ[5]s connected via their bound K+ ions in a triangular manner in which the coordination of each K+ ion to the five portal carbonyl oxygen atoms of one SQ[5] as well as to a bridging portal carbonyl oxygen from an adjacent SQ[5] draws the edges of three portals into close proximity. The corresponding offset angle at each junction provides the basis for the 3D assembly of the observed fused 10-membered SQ[5] bracelet frameworks.

In this paper we propose a variant of the continuous-time Markowitz mean-variance model by incorporating the Earnings-at-Risk measure in the portfolio optimization problem. Under the Black-Scholes framework, we obtain closed-form expressions for the optimal constant-rebalanced portfolio (CRP) investment strategy. We also derive explicitly the corresponding mean-EaR efficient portfolio frontier, which is a generalization of the Markowitz mean-variance efficient frontier.

We introduce an approach for the synthesis of networks based on the coordination of alkyl-substituted cucurbit[5]uril (SQ[5]), dimethylcucurbit[5]uril (DMeQ[5]), 1,3-dicyclohexanocucurbit[5]uril (1,3-DCyHQ[5]), 1,2,4-tricyclohexanocucurbit[5]uril (1,2,4-TriCyHQ[5]), 1,2,3-cyclohexanocucurbit[5]uril (1,2,3-TriCyHQ[5]), and pentacyclopentanocucurbit[5]uril (PCyPQ[5]) with K+ ions in the absence of a structure inducer. These novel SQ[5]-K+-based networks feature trigonal-planar branches constructed from three SQ[5]s and K+ ions in a triangular manner, in which the coordination of each K+ ion to the five portal carbonyl oxygen atoms of one SQ[5] as well as to a bridging portal carbonyl oxygen from an adjacent SQ[5] draws the edges of three portals into close proximity. Thus, a 3-K+-cation junction is formed at each portal of the S[5] and there are four 3-K+-cation junctions in which one or two coordinated water molecule(s) are shared by the three K+ cations in the trigonal-planar branch. Detailed inspection of the relationship of the planes at the 3-K+ junction has revealed that the dihedral angles between the junction plane and the center junction plane have a strong influence on the supramolecular assembly of SQ[5] with K+ ions into 2D-networks or 3D-frameworks. Moreover, these dihedral angles determine the structural conformation of the SQ[5]-K+-based networks and the superimposition of 2D-networks in the compounds.