active ingredient in cialis The euro zone's landmark buildings are seen at the headquarters of the European central bank (ECB) in Frankfurt In the early 20th century, famous American economist elvin fisher developed the theory of economic gain. In its book "the nature of capital and yield", first, the concept of yield is analyzed in terms of the performance of earnings, and three different types of benefits are proposed: For many, the first benefit of entering the blockchain and cryptocurrency world could be economic gain. But the DRAM and NAND semiconductor industries have gone from boom to bust in the face of rising prices and the abundance of falling prices. Will it be any different this time? Or is the need for mobile device memory and disk replacement sufficient to continue to delay the abundance until the foreseeable future?