Marginal Return of Infrastructure Investment on Bilateral Trade Performance

Investing in transport infrastructures such as roadways, airports and seaports has proven to improve a country's trade performance through reduction of transportation costs and providing access to production and market. This research investigates the diminishing return of infrastructure investment and also the rate of return of two types of infrastructure investment strategies on trade. An augmented gravity model is used with econometric analysis methods in this study. The results have shown that as roadway and airport densities increase, the marginal returns on trade decrease. Empirical evidence from the United States and China with all their trading partners from the past twenty years has also suggested existence of diminishing return of infrastructure investment on roadways and airports. Infrastructure investment strategy that focuses on increasing roadway and airport density experiences smaller diminishing return on trade. In contrast, seaport investment that focuses on port quality and efficiency generates higher return on trade. A trade benefiting infrastructure investment strategy that best utilizes financial resources must balance between quality and quantity based on a country's current level of infrastructure asset.

The Resilience of Self-Esteem in Late Adulthood

OBJECTIVE: The authors examined the resilience of self-esteem after loss in the lives of older adults. Specifically, the authors investigated the relationship between loss and change in self-esteem during a 3-year period. METHOD: A subsample of older adults (n = 1,278) from the Americans' Changing Lives Study was used to examine loss in the domains of health, financial security, or work and career and self-esteem before and after the loss. RESULTS: There was a small but significant decrease in self-esteem between Wave I and Wave II of the study. Loss in one of the domains explained less than 1% of the variance in self-esteem change. DISCUSSION: The low incidence of loss and small change in high levels of self-esteem are further evidence of resilience in older adults' psychological well-being. The implications for older adults' use of cognitive strategies to manage losses and promote gains are discussed.