Many alien species become invasive because they lack coevolutionary history with the native community; for instance, they may lack specialized enemies. These evolutionary advantages may allow the invader to establish and persist when rare within a community and lead to its monodominance through positive frequency dependence, i.e. increasing per capita population growth rate with increasing freq...

during recent years, a debate has been taking place on the relationship between economic growth and trade policies. the present article explores the impact of trade liberalization on economic growth in islamic countries. we chose a sample of 26 islamic countries and using the gmm method, estimated the correlation between trade liberalization and economic growth for the period 1990-2003. the emp...

The population structure of the Toto tribe at Totopara, a small village in West Bengal, District Jalpaiguri, is studied in this report. Since 1951 the Totos have been coming more and more in contact with the outside world and undergoing a process of cultural and developmental change. Using data from census records for the years 1901, 1911, 1921, 1931, 1951 and 1979-80, as well as interviews w...