Search

We develop a dynamic equilibrium model of insurance pricing in a competitive market consisting of heterogeneous insurance companies. The insurers have different beliefs on expected loss rate of an underlying risk process and the belief divergences are stochastic. The insurers select optimal insurance market shares to maximize their individual utilities. The equilibrium insurance price is formulated when the insurance market is cleared. We provide a general equilibrium framework with a continuum of insurers in the market and then solve for the equilibrium insurance price explicitly in the case of N insurers. We find that the stochastic heterogeneity brings extra volatility to insurance price and makes it dynamic. The mean-reverting divergences of insurers may explain cycles of insurance business documented by empirical studies. Compared to the previous literature of optimal insurance, this paper introduces an asset pricing framework of general equilibrium to the research of insurance pricing. [ABSTRACT FROM AUTHOR]

Core–shell structured Fe-Si-Al@TiO2 with uniform coating layers have been used for preparing soft magnetic composites (SMCs) with good magnetic properties. The quality of the TiO2 insulation layer has been optimized by tuning the content of tetrabutyl titanate (TBOT), the reaction time, and the volume of acetic acid. It is proved that the conditions of 5 ml TBOT, 1-h reaction time, and 100 µl acetic acid would lead to uniform and dense TiO2 layer. As a result, the high-frequency eddy-current loss can be effectively decreased, which is related with increased resistivity. Moreover, optimal Fe-Si-Al@TiO2 powders would ensure high density of SMCs, resulting in high effective permeability and low hysteresis loss. When the effective permeability of optimal SMCs reaches 85 (measured at 100 kHz/1 V), the core loss is only 691.33 mW/cm3 (measured at 500 kHz/50 mT), which is much lower than those of Fe-Si-Al SMCs insulated with Al2O3 and phosphate. Owing to high-quality TiO2 insulating layer, as-prepared SMCs show unique superiority in achieving high effective permeability and low core loss simultaneously, in contrast with other reported SMCs. This work may provide novel insights into the synthesis of SMCs with excellent magnetic properties via building uniform oxide coating layer. [ABSTRACT FROM AUTHOR]

We solve an optimal portfolio choice problem under a no-borrowing assumption. A duality approach is applied to study a family’s optimal consumption, optimal portfolio choice, and optimal life insurance purchase when the family receives labor income that may be terminated due to the wage earner’s premature death or retirement. We establish the existence of an optimal solution to the optimization problem theoretically by the duality approach and we provide an explicitly solved example with numerical illustration. Our results illustrate that the no-borrowing constraints do not always impact the family’s optimal decisions on consumption, portfolio choice, and life insurance. When the constraints are binding, there must exist a wealth depletion time (WDT) prior to the retirement date, and the constraints indeed reduce the optimal consumption and the life insurance purchase at the beginning of time. However, the optimal consumption under the constraints will become larger than that without the constraints at some time later than the WDT. [ABSTRACT FROM PUBLISHER]

In this paper, we consider an optimal reinsurance problem. The surplus model of the insurance company is approximated by a diffusion model with the drift coefficient μ. The insurance company employs reinsurance to reduce the risk. π is the proportion of each claim paid by the company and the remainder proportion of the claim is paid by the reinsurer. λ(1 − π) is the rate at which the premiums are diverted to the reinsurer, thus it holds λ ≥ μ > 0 in general. We discuss two cases: (i) non-cheap reinsurance (when λ > μ), (ii) cheap reinsurance (when λ = μ). The objective of the insurance company is to make an optimal decision on reinsurance to reach a goal (a given surplus level) in minimal expected time. We disclose that for some case it is not suitable to search optimal decisions by minimizing the expected time to reach a goal. In order to deal with this case, we study two other methodologies (ruin probability minimization and expected discount factor maximization) for the optimal strategy selection problem in reinsurance decision. [ABSTRACT FROM AUTHOR]

We consider a multi-stock market model. The processes of stock prices are governed by stochastic differential equations with stock return rates and volatilities driven by a finite-state Markov process. Each volatility is also disturbed by a Brownian motion; more exactly, it follows a Markov-driven Ornstein–Uhlenbeck process. Investors can observe the stock prices only. Both the underlying Brownian motion and the Markov process are unobservable. We study a discretized version, which is a discrete-time hidden Markov process. The objective is to control trading at each time step to maximize an expected utility function of terminal wealth. Exploiting dynamic programming techniques, we derive an approximate optimal trading strategy that results in an expected utility function close to the optimal value function. Necessary filtering and forecasting techniques are developed to compute the near-optimal trading strategy. [ABSTRACT FROM AUTHOR]

Cardiovascular diseases are the main cause of death and disability among diabetes patients. Atherosclerosis-associated stroke is one of the most severe complications in diabetes patients. DPP-4 inhibitors are a class of potent anti-glycemic agents used to treat diabetes. Recently, some DPP-4 inhibitors have been shown to have cardiovascular benefits. In this study, we reveal that saxagliptin, one of the most widely used DPP-4 inhibitors, exhibits vascular protective effects against oxygen and glucose depletion/reoxygenation (OGD/R) in human brain vascular endothelial cells. Our data show that DPP-4 is fairly expressed in brain endothelial cells and its expression is induced by OGD/R. The results of MTT assay show that inhibition of DPP-4 by saxagliptin ameliorates OGD/R-induced reduced cell viability, and LDH assay demonstrated that saxagliptin reduces cellular toxicity. Furthermore, we show that saxagliptin mitigates OGD/R-induced collapse of mitochondrial membrane potential (MMP). Saxagliptin also reduces oxidative stress-induced release of 4-HNE and the NAPDH oxidase catalytic subunit NOX-4. At the molecular level, saxagliptin suppresses OGD/R-induced expression of pro-inflammatory cytokines and production of vascular adhesion molecules including tumor necrosis factor-α (TNF-α), interleukin (IL)-6, monocyte chemoattractant protein 1 (MCP-1), vascular cellular adhesion molecule 1 (VCAM-1), and E-selectin. Mechanistically, saxagliptin inhibits activation of the NF-κB pathway by OGD/R via its inhibitory effect on nuclear p65 and NF-κB promoter activity. Collectively, our study explicitly demonstrates the cellular protective effect of saxagliptin against OGD/R-induced brain endothelial injury. Our findings extend our recognition of the protective roles of DPP-4 inhibitors in brain vascular cells., Competing Interests: None., (AJTR Copyright © 2019.)