jalal al-e-ahmad relying on the popular and lively language of his society has used a unique and dynamic language in his works. this unique feature has reached to its summit in the school principal in which the characters from each social class in the story use the language of the same class in the real society. in order to reach a deeper understanding of this masterpiece, this article compares...

While parasites and immunity are widely believed to play important roles in the evolution of male ornaments, their potential influence on systems where male weaponry is the object of sexual selection is poorly understood. We experimentally infect larval broad-horned flour beetles with a tapeworm and study the consequent effects on: 1) adult male morphology 2) male-male contests for mating oppor...

I present a notion of invariance under arbitrary surjective mappings for operators on a relational finite type hierarchy generalizing the so called Tarski-Sher criterion for logicality and I characterize the invariant operators as definable in a fragment of the first-order language. These results are compared with those obtained by Feferman and it is argued that further clarification of the not...