Roughness coefficient and its uncertainty in gravel-bed river

Manning's roughness coefficient was estimated for a gravel-bed river reach using field measurements of water level and discharge,and the applicability of various methods used for estimation of the roughness coefficient was evaluated.Results show that the roughness coefficient tends to decrease with increasing discharge and water depth,and over a certain range it appears to remain constant.Comparison of roughness coefficients calculated by field measurement data with those estimated by other methods shows that,although the field-measured values provide approximate roughness coefficients for relatively large discharge,there seems to be rather high uncertainty due to the difference in resultant values.For this reason,uncertainty related to the roughness coefficient was analyzed in terms of change in computed variables.On average,a 20%increase of the roughness coefficient causes a 7% increase in the water depth and an 8% decrease in velocity,but there may be about a 15% increase in the water depth and an equivalent decrease in velocity for certain cross-sections in the study reach.Finally,the validity of estimated roughness coefficient based on field measurements was examined.A 10% error in discharge measurement may lead to more than 10% uncertainty in roughness coefficient estimation,but corresponding uncertainty in computed water depth and velocity is reduced to approximately 5%.Conversely,the necessity for roughness coefficient estimation by field measurement is confirmed.     

Managers' Trading Around Stock Repurchases

We analyze personal open market trades by managers around stock repurchases by tender offer. With the exception of Dutch auction offers, managers trade their firm's shares prior to repurchase announcements as though repurchases convey favorable inside information to outsiders. Prior to fixed price repurchase offers that do not follow takeover-related events, managers increase their buying and reduce their selling of their firm's shares. Prior to repurchases that follow takeover-related events, only a decrease in selling is found. No abnormal trading precedes Dutch auction repurchase offers.     

Market Integration and Price Execution for NYSE-Listed Securities

For New York Stock Exchange (NYSE) listed securities, the price execution of seemingly comparable orders differs systematically by location. In general, executions at the Cincinnati, Midwest, and New York stock exchanges are most favorable to trade initiators, while executions at the National Association of Security Dealers (NASD) are least favorable. These intermarket price differences depend on trade size, with the smallest trades exhibiting the biggest per share price difference. Collectively, these results raise questions about the adequacy of the existing intermarket quote system (ITS), the broker's fiduciary responsibility for “best execution,” and the propriety of order flow inducements.     

Climbing the Job Ladder: New Evidence of Gender Inequity

An explanation for the gender wage gap is that women are less able or less willing to “climb the job ladder.” However, the empirical evidence on gender differences in job mobility has been mixed. Focusing on a subsample of younger, university‐educated workers from an Australian longitudinal survey, we find strong evidence that the dynamics of promotions and employer changes worsen women’s labor market position.     

MEASURING PRICE ELASTICITY OF SECTORIAL IMPORTS

Previous published studies have estimated the long‐run cointegrating relationship to infer the price elasticity of imports, but a stable long‐run cointegrating relationship might not be detected in the data, especially in the case of sectoral data. This paper develops a method to estimate the price elasticity of imports based on a vector autoregression model, which can be applied when a stable long‐run cointegration relationship does not exist. The methods developed in past studies and our method are applied to Korean sectoral imports data to illustrate the usefulness of our method.     

INFLATION TARGETING IN PRACTICE: FURTHER EVIDENCE

This paper empirically investigates the plausibility, which has been argued but not fully established, that the efficacy of the inflation-targeting strategy recently implemented by New Zealand, Canada, and the U.K. has been an artifact of a global disinflationary environment. A data decomposition procedure, which involves cointegration and canonical correlation analysis, is used to remove common trend and cyclical components from historical data that these three countries share with their nontargeting neighboring countries, namely, Australia, the U.S., and Germany, respectively. Simulations based on resulting country-specific data for inflation and other economic aggregates reveal scant evidence of regime-shift effects as exhibited in observed data. This contrast in findings highlights the extent to which cross-country synchronization in economic activity has on the performance of small open economies. (JEL C32, E52, E58)     

Optimal Schooling Investments and Earnings: An Analysis Using Australian Twins Data

The potential impact that unobserved ability can have on both schooling and earnings outcomes has been modelled by Ashenfelter and Rouse (1998). This paper applies their model to the Australian Twins Sample. The best estimate of the return to schooling for genetically identical (or MZ) twins is 8.9 per cent. Measurement errors in the schooling data are shown to constitute a more serious problem than the omission of the family effects that impact on ability. Individuals from higher ability families receive a lower marginal benefit from their investment in human capital.