Multicast 1 is one of the best available service models for scalable, many-to-many delivery of data on the Internet. Multicast achieves scalability by letting sources send a packet only once, regardless of the number of receivers. In network-layer multicast, network elements (routers, switches, and so on) replicate packets at network branching points, delivering copies to all interested receive...

instrumentalism (in the science) refers to a view that considers scientific theories as nothing more than instruments for prediction. sometimes the traces of this attitude have been searched in the writings of plato and aristotle; but mostly the pioneers of the theory have been thought to be the priests who regarded the scientific propositions as mere hypothesis, in order to defend religious do...

after the prophet death (pbuh), imam ali and other innocent             imams took efforts on protection, revival and teaching           prophetic tradition which was the interpretation of the holy   quran. they did necessary actions in this case such as:    invitation of imam ali from public to question about qur'anic exegesis, holding special sessions to teach quran     and its interpret...