Christopher H. Wheeler is a research officer in the Research division of the Bank. He previously was an assistant professor of economics at Tulane University in New Orleans. Wheeler received his doctoral and master’s degrees in economics from the University of Wisconsin-Madison in 1998 and 1995, respectively, and his bachelor’s degree in economics from Colby College in Waterville, Maine, in 199...

‎there is a flatness property of acts over monoids called condition $(pwp)$ which‎, ‎so far‎, ‎has received‎ ‎much attention‎. ‎in this paper‎, ‎we introduce condition gp-$(p)$‎, ‎which is a generalization of condition $(pwp)$‎. ‎firstly‎, ‎some  characterizations of monoids by condition gp-$(p)$ of their‎ ‎(cyclic‎, ‎rees factor) acts are given‎, ‎and many known results are generalized‎. ‎more...

the selection of high yielding varieties with good stability‏ ‏is an important objective in rice breeding ‎programs. the grain yield of eight rice lines with a check (nemat) were compared‎‏ ‏on six locations of gilan ‎and mazandaran provinces during two years, using rcbd with four replications. combined analysis of ‎variance showed that the effect of variety and year ‎‏×‏‎ location ‎‏×‏‎ variet...