Movements in the external value of currencies have direct and indirect effects on plenty of macroeconomic variables such as inflation, exports, output, profits and - ultimately - jobs. This week we have seen the Japanese central bank intervening in the foreign exchange market in an attempt to drive the value of the Yen lower. Japan is struggling to sustain a recovery after the global financial crisis and a weaker currency is seen as a vital part of the attempt to prevent another draining bout of price deflation.

And the long-running dispute between the United States and China about the alleged under-valuation of the Yuan against the US dollar continues to rumble. This BBC news video takes a swing through New Jersey to find trade unions lobbying government for more action on the exchange rate issue.