Personal identity has many facets, as it involves race, language, personal interests, religion, and ethnicity, among other attributes. Yet all over the world individuals and groups seek to define themselves in exclusive terms. This paper develops a simple model of individual incentives and group interests to explain this puzzle. ∗Faculty of Economics, University of Cambridge. †Faculty of Econom...

some chemical characteristics of root, shoot and litter of index species such as salsola rigida, artemisia sieberi and stipa barbata commonly used in rangeland development projects were evaluated and compared. chemical properties of soil under and between the above mentioned species were also studied. for this purpose, vegetation types of stipa barbata and artemisia sieberi - salsola rigida wer...