China has gradually raised the statutory retirement age and introduced a flexible retirement mechanism to address the financial sustainability challenges of its pension system. These reforms, by granting individuals greater flexibility over when to retire, highlight the importance of understanding how social insurance and health risks jointly shape individual retirement behavior. Against this background, this paper develops a structural retirement model incorporating endogenous health risks and calibrates its parameters using the simulated method of moments to examine the behavioral effects of social insurance on retirement decisions. The results show that higher wage levels encourage individuals to extend their working life and delay retirement, whereas health shocks, through their adverse effect on earnings, lead to earlier labor market exit. The introduction of basic pension insurance tends to induce earlier retirement, while basic medical insurance postpones it. Enhancing basic pension benefits further encourages earlier retirement, whereas increasing personal account pension benefits delays it due to the investment nature of personal accounts. Moreover, expanding medical insurance benefits has two main effects: it weakens the incentive for precautionary savings, leading to earlier retirement, while also increasing medical expenditures and extending life expectancy through improved access to healthcare.

China's persistently low fertility is associated with fertility inequality, reflected in a U-shaped relationship between household human capital and fertility. We develop an overlapping-generations model showing that this pattern depends on the substitutability of educational inputs. When educational inputs are complementary, fertility is U-shaped in household human capital, with middle-human-capital households having the fewest children; when inputs are substitutable, the relationship is inverted U-shaped. Using China Family Panel Studies data, we find a robust U-shaped relationship between household human capital and fertility, significant complementarity among educational time, monetary investment, and household human capital in children's human-capital formation, and similar patterns across eastern, central, and western China. Complementarity requires households to increase time and monetary inputs jointly, intensifying the quantity-quality trade-off, particularly for middle-human-capital households. Policies that enhance substitutability among educational inputs may therefore mitigate fertility inequality and raise aggregate fertility.

This study introduced a vacuum-stabilized lung window technique for intravital imaging, which for the first time enabled the simultaneous, high-resolution, real-time monitoring of both pulmonary arterial vascular reactivity and dynamic changes in intracellular calcium signaling smooth muscle cells during acute hypoxic pulmonary vasoconstriction (HPV) in spontaneously breathing mice. By integrating two-photon microscopy with intravascular fluorescent tracers (FITC, Evans Blue) and a smooth muscle-specific genetically encoded calcium indicator (GCaMP6f), this technique enabled stable imaging of pulmonary arteries within a diameter range of 13.95–80.16 μm and supported the systematic extraction and analysis of calcium signals from multiple regions of interest along the longitudinal axis of the vascular wall. Acute hypoxia (10

In this paper, the authors investigate the optimal per-claim reinsurance problem under the continuous-time framework to minimize the insurer’s ruin probability based on the Lundberg exponent. Considering reinsurance participants’ diversified risk preferences, the authors assume that the reinsurance premium is calculated by a combined premium principle, including the expected value premium principle and upper moment premium principle. Then, the authors derive the insurer’s optimal reinsurance strategy satisfying the principle of indemnity and the incentive compatibility condition in an infinite reinsurance space based on the point-wise optimization approach. Besides, the proposed work emphasizes the optimality and admissibility of the combination of the excess of loss reinsurance and its dual form when a piecewise reinsurance premium principle is considered. As a special case, the optimal reinsurance strategy under the expected value premium principle reduces to the classic result. Furthermore, the numerical analyses are provided to illustrate the effects of the main parameters on the maximal Lundberg exponent and the optimal reinsurance strategy.

Lung cancer patients tend to have strong intratumoral and intertumoral heterogeneity and complex tumor microenvironment, which are major contributors to the efficacy of and drug resistance to immunotherapy. From a new perspective, single-cell techniques offer an innovative way to look at the intricate cellular interactions between tumors and the immune system and help us gain insights into lung cancer and its response to immunotherapy. This article reviews the application of single-cell techniques in lung cancer, with focuses directed on the heterogeneity of lung cancer and the efficacy of immunotherapy. This review provides both theoretical and experimental information for the future development of immunotherapy and personalized treatment for the management of lung cancer.

Social distancing restrictions have become a primary measure in curbing the spread of the COVID-19 pandemic. Given the fact that the survival probability of infected individuals and labour supply will decline during the pandemic, this study extends the overlapping generations (OLG) model to include the effects of COVID-19 on individuals' health and investigates the optimal social distancing policy from an economic perspective. Our results show that the pandemic can cause economic contraction, and a strict social distancing policy generally benefits economic growth. Nevertheless, absolute zero socializing may not be an optimal strategy.

We apply the simulated method of moments to a lifecycle model to infer the impact of health insurance on life expectancy. The model features endogenous health risks, which are determined jointly by the natural law and one’s own decisions of medical care expenditures. Individual’s optimal decisions of consumption, saving, and medical care expenditure are solved, and life expectancies are calculated in the scenarios with and without health insurance. The comparison result shows that health insurance has a positive impact on life expectancy through its positive impact on medical care expenditures, but this impact is not quantitatively significant.

Background Family education investment is a key factor in reducing intergenerational transmission of poverty. At the price of higher health risk, the poor may overdraw their bodies to earn more money to invest in education. This study investigates the effect of physical overdraft, health risks and health insurance on poverty and economic growth. Methods This paper proposes an economic development model of endogenous health risks and poverty by setting up a physical overdraft decision. Furthermore, we introduce mutual health insurance mechanism to analyze its poverty alleviation effects. Results First, this study shows that health risks weaken the economy and are among the leading causes of poverty. Second, mutual health insurance can alleviate, but not completely eliminate, the negative impact of health risks on the economy. Third, appropriate health insurance arrangements can lift some or even all poor households out of poverty. Conclusion Health risks have a significant effect on poverty. Furthermore, health insurance mechanisms have the advantages of transferring health risks, reducing poverty and improving health equity.

在我国生猪期货市场初步建立且中小规模养殖户较多的背景下,生猪价格指数保险是利用保险方式抑制"猪周期"的有益探索.本文基于对生猪市场供需关系的实证分析,结合蛛网理论和ARMA模型对生猪价格周期进行预测,并评估了生猪价格指数保险对"猪周期"的抑制效果.结果显示,模型预测的生猪价格波动趋势呈现出收敛型的蛛网特征,其中大周期为4～6年,小周期为5～14个月.在本文的研究框架下,生猪价格指数保险对"猪周期"产生了明显的抑制作用,并且在合理区间内,约定猪粮比越高,抑制效果越好;同时,生猪价格偏离均衡价格越远,生猪价格指数保险对价格波动的抑制效果越明显.

Understanding COVID-19 induced mortality risk is significant for life insurers to better analyze their financial sustainability after the outbreak of COVID-19. To capture the mortality effect caused by COVID-19 among all ages, this study proposes a temporary adverse mortality jump model to describe the dynamics of mortality in a post-COVID-19 pandemic world based on the weekly death numbers from 2015 to 2021 in the United States. As a comparative study, the Lee-Carter model is used as the base case to represent the dynamics of mortality without COVID-19. Then we compare the force of mortality, the survival probability and the liability of a life insurer by considering COVID-19 and those without COVID-19. We show that a life insurer's financial sustainability will deteriorate because of the higher mortality rates than expected in the wake of COVID-19. Our results remain unchanged when we also consider the effect of interest rate risk by adopting the Vasicek and CIR models.

保险公司资产配置需要同时考虑资产负债匹配和风险-收益均衡.本文在偿二代对保险资产负债匹配的隐性要求和保险资产负债管理监管规则对资产负债匹配的显性要求下,考察了资本占用和久期匹配约束下的险资投资策略,研究了保险公司的最优资产配置问题.结果 显示:负债久期较长的寿险公司很难同时满足偿二代资本要求和资产负债久期匹配要求;保险资产负债管理监管规则对保险公司资产配置策略产生显著影响;资产收益特征设定下,保险公司资产配置策略有改进空间.本文的创新点是依据保险资产负债管理监管规则显性地引入资产负债匹配要求,同时在偿二代与资产负债匹配约束下研究了寿险公司最优资产配置.

This paper explores the role of basic medical insurance in protecting family investment in child education. First, this paper establishes a two-phase overlapping generation model to theoretically analyse the impact of basic medical insurance on investment in child education under the influence of the impact of parental health. The results show that health shock reduces parental investment in child education, and medical insurance significantly alleviates the negative impact of parental health shock on investment in child education. Furthermore, this paper establishes a two-way fixed effect regression model based on the data of China Family Panel Studies (CFPS) in 2014 and 2016 to empirically test the above results. The results showed that parental health shocks negatively affect investment in child education, and paternal health shock has a more significant impact than maternal health shock. However, medical insurance significantly reduces this negative impact, provides security in investment in child education, and promotes the improvement of human capital.

The sustainability of China’s Basic Pension System (CBPS) has been challenged by the ageing of the population and the decline in economic growth. This article establishes a Markov model for CBPS to examine whether the reforms, including ending the one-child policy and raising retirement the age, will shrink the negative income–expenditure gap. We find that the negative income–expenditure gap will destroy CBPS in the future in the absence of fiscal transfer or reform. Ending the one-child policy will increase the number of contributors and then reduce the gap in the short term but will worsen the gap in the long term. Raising the retirement age will have several positive effects overall while increasing expenditures in certain periods. The contributions of this article are describing CBPS in detail and establishing a precise model to analyze the effectiveness of reforms.

本文以非寿险业务保险风险最低资本要求为考察对象,研究了欧盟Solvency Ⅱ与中国C-ROSS的差异,并利用中国保险市场60家财险公司的经验数据,对两者之间的差异进行了实证和模拟分析.研究结果表明,Solvency Ⅱ和C-ROSS对中国财险公司保险风险最低资本要求存在差异.对于拥有传统业务结构的财险公司,Solvency Ⅱ对保险风险最低资本要求更高,但是这种差距随着公司业务规模的缩小而减弱;对于以经营某些专业险种为主的财险公司,主营业务险种对两者差异具有决定性影响.本文的研究结论详细解释了Solvency Ⅱ与C-ROSS在非寿险保险风险最低资本计算上的异同,对C-ROSS下一步的修订工作提供了一定的支持与参考.

This paper considers a risk poverty trap model in which technology adoption depends on the individual's capital level. Agricultural insurance and premium subsidies are then introduced to analyse poverty alleviation resulting from agricultural insurance. For individuals with capital above a threshold, insurance can be helpful, since it lets them stay above the threshold. Agricultural insurance does not help peasants escape deep poverty, because premiums keep them below the threshold. Moreover, premium subsidies would strengthen the poverty reduction resulting from insurance, as the increased income and the risk elimination would move some peasants above the critical threshold.

农村金融是农村经济发展的重要内生动力,创新金融扶贫体制对我国农村深度贫困地区的脱贫攻坚工作具有重要意义.本文基于多重均衡模型,对比研究信贷、保险、“信贷+保险”三类金融产品的扶贫效果,在不同的信贷和保险产品结构下得出陷贫概率,进而得出金融扶贫产品的精准设计,以创新金融扶贫体制,从而解决我国深度贫困的问题.研究表明:单独信贷产品扶贫无效;保险能够帮助阈值以上人群摆脱潜在贫困,但对深度贫困无效;“信贷+保险”能解决一定程度的深度贫困问题,比单独信贷或单独保险的扶贫效果更好.

小额保险不仅是金融精准扶贫的重要手段也是精准扶贫体系的重要支撑工具.本文基于前景理论和农村居民收入水平的实际情况,结合精准扶贫内涵,建立了一个评价保险减贫效应的动态系统理论模型,借此讨论小额保险精准扶贫效应问题.研究发现:保险对农村不同收入水平的个体的减贫效应存在差异,本文将扶贫对象精准划分为显性贫困、潜在绝对贫困和潜在相对贫困三类;农村小额保险能有效减少农村绝对贫困总人数和相对贫困总人数,并且传统保险也能大幅改善农村相对贫困现状,但是传统保险会恶化农村绝对贫困现状;单独的保险工具无法彻底解决深度贫困(显性贫困)问题,而作为金融扶贫的一种创新模式,“小额保险+信贷”是解决深度贫困(显性贫困)问题的有效工具.

This work uses different classes of premium principles (including the expected value premium principle, the variance premium principle and the exponential premium principle) as well as optimal reinsurance problems to minimize the probability of ruin and maximize the expected utility in both a diffusion insurance risk model and a compound Poisson insurance risk model. The optimal reinsurance strategy with a nontrivial structure and its respective optimal value function are obtained. Specifically, the optimal reinsurance strategy has a curved form, which is distinguished from the conventional proportional and excess-of-loss reinsurance strategies. Numerical analyses are provided to illustrate the behaviors of the optimal reinsurance strategies under different objective criteria and different insurance risk processes.

个人税收递延型商业养老保险试点对促进养老保险发展、提高国民养老保障水平具有重要意义.实施商业养老保险个人税收递延政策后,政府为应对税收收入下降,可采用降低财政支出、发行政府债券、提高个人所得税税率三种不同的财政政策措施.运用宏观经济均衡的OLG模型,研究上述三种不同财政政策措施对经济均衡及个人、企业最优缴费率的影响.结果表明:三种财政政策措施都能提高居民退休期消费和居民效用;发行政府债券能够较大幅度提高居民的退休期消费,但会对经济增长产生一定的负面影响,而减少财政支出和提高个人所得税税率有助于促进经济增长,但对居民退休期消费的正向影响较小;减少财政支出和提高个人所得税税率会大幅降低社会基本养老保险最优个人缴费率并小幅提高最优企业缴费率,发行政府债券对缴费率的影响正好相反.本文研究结论的政策启示是:有关部门需要为个人税收递延型商业养老保险的试点和推广做好财政政策及配套政策的研究和储备,确保预期政策目标的顺利实现;同时考虑对基本养老保险缴费率组合进行调整,实现社会福利的帕累托改进.