among the low–dimensional allotropes of carbon, nanotubes and graphene have attracted very much attention from nano–science and nanotechnology specialists. they have been proposed as building blocks in nanometer device engineering. however, these structures are not defect–free. in this thesis, we focused on defective carbon nanotubes and graphene, and studied the effect of couple of very common...

abstract u.s. attack to afghanistan after 9/11 provided opportunities for us who tried to become the dominant power after collapse of ussr and bipolar world. thinkers like fukuyama believed american liberal democrats thought would be universally accepted without resistances. liberal democracy is the best and final model of governance; in this regard, united state has moral responsibilities for...

Wildlife is an important biological indicator of viability of ecosystems, therefore, understanding habitat requirements of species is essential for biodiversity conservation. Determining the suitability of habitats for wildlife is important for effective management and conservation of species. The brown bear (Ursus arctos), as the largest carnivorous mammal in Iran, is distributed in most fores...

Adequate knowledge about suitable habitats for wildlife is essential to prevent habitat destruction and extinction of species and for their conservation and management. The Eurasian lynx is one of the mostly distributed cats in Asia. In this study, we applied an ensemble habitat suitability modeling approach, using ten predictor variables to model Eurasian Lynx’s habitat suitability in Saveh Za...

Habitat suitability models for the focal species are used to address the concerns related to the limited availability of data for remote habitats by scrutinizing the relationship between the biodiversity distribution patterns and the natural-anthropogenic characteristics. The current study aimed at modeling habitat suitability for seven focal species including Asian black bear, Persian leopard,...

abstract the purpose of this study is twofold: on the one hand, it is intended to see what kind of noticing-the –gap activity (teacher generated vs. learner generated) is more efficient in teaching l2 grammar in classroom language learning. on the other hand, it is an attempt to determine which approach of the noticing-the-gap- activity is more effective in the long- term retention of grammar...

the purpose of the present study was to investigate the effect of task-based instruction of vocabulary on the receptive and oral productive acquisition of english vocabulary and compare the results with those obtained from the traditional method. the method and procedure applied in this study was as follows: after the implementation of opt, a group of sixty female students were chosen. the stu...

there are two major theories of measurement in psychometrics: classical test theory (ctt) and item-response theory (irt). despite its widespread and long use, ctt has a number of shortcomings, which make it problematic to be used for practical and theoretical purposes. irt tries to solve these shortcomings, and provide better and more dependable answers. one of the applications of irt is the as...