Number Of Empirical Methods Research Articles

Closure to “Pile Setup in Cohesive Soil. I: Experimental Investigation” by Kam W. Ng, Matthew Roling, Sherif S. AbdelSalam, Muhannad T. Suleiman, and Sri Sritharan

Closure to “Pile Setup in Cohesive Soil. I: Experimental Investigation” by Kam W. Ng, Matthew Roling, Sherif S. AbdelSalam, Muhannad T. Suleiman, and Sri Sritharan

Long‐Run Performance of Chinese Initial Public Offerings: Further Evidence*

AbstractThis study examines the long‐run performance of 936 Chinese initial public offerings (IPOs) over the period 1996 to 2005 (the post‐issue return evidence ends in June 2008). Using a number of empirical methods, including event‐time and calendar‐time approaches based on a size and industry matching firm benchmark, we find a significant long‐run overperformance using the equal‐weighted buy‐and‐hold abnormal returns, although not for the value‐weighted returns, suggesting that the performance of small‐size IPO firms is superior to that of large‐size IPO firms. The significant overperformance disappears, however, when using cumulative or calendar‐time abnormal returns. The preset study provides out‐of‐sample evidence in an emerging market context in support of Fama's (1998) argument that reported long‐run performance is sensitive to the method of analysis. Finally, based on a rich set of explanatory factors as proxies for both signaling and ex‐ante uncertainty characteristics, our results are supportive of the signaling hypothesis, but inconsistent with the divergence of opinion hypothesis.

Empirical Modeling of Relationships Between Sorghum Yield and Soil Properties

A crucial part of any site-specific management is the identification of causes of yield variability and assessment of crop requirements. Therefore, relationships between yield and soil properties must be identified. In this study, relationships between sorghum yield and soil properties on a verbosols within a field located in Moree, in northern NSW, Australia, were examined. Measured soil properties included pH; available phosphorus; percent clay, silt and sand; gravimetric moisture content of air-dry soil and at matric potentials corresponding to −1 500 kPa and −33 kPa; percent organic carbon; CEC and exchangeable calcium, magnesium, sodium and potassium and copper, zinc, manganese and iron contents. The exchangeable sodium percentage (ESP) and the Ca/Mg ratio were calculated. We used a number of empirical methods and found that neural networks, projection pursuit regression, generalized additive models and regression trees are good techniques for modeling yield response. However, further comparison of these techniques is needed. By modeling yield response to individual soil properties and using kriging to map yields predicted from these models, it was possible to identify which soil properties limited production in different areas of the field.

“Equivocalness” and Other Empirical Methods in Zygosity Assessment

Zygosity determination is generally carried out by different methods in small or large twin samples. The probability method based on sex and genetic markers is limited to relatively small samples, as a consequence of its cost. The empirical questionnaire method is applied in several large twin registers. Its margin of error is low enough for population studies, its cost is negligible, but its accuracy is insufficient when zygosity of twin pairs included in definite samples must be individually assessed. Efforts to bridge the distance between the two methods should be made, and they may take either direction: (1) find new, inexpensive genetic markers, or (2) increase the number and accuracy of empirical methods. The accuracy of a number of empirical methods applied to a twin sample of established zygosity has been compared. One modification of the “two peas in a pod” method, originally called “equivocalness method”, appears to warrant inclusion in questionnaire methodology. Also, compound probability as expressed by several empirical methods may reach an acceptable level of accuracy in zygosity assessment.

To the method of growing anaerobic cultures

The method of growing anaerobes has not yet been sufficiently developed. A number of empirical methods have been proposed that give excellent results when growing one or another pathogen; but the use of these methods is often difficult, due to their complexity, and in addition, the factors contributing to growth, when applying a particular method, are not sufficiently understood.