The implied rise from money market rates is also shown on the graph. The principal fear of the Fed ­ and all central banks ­ is that there might be a rerun of 1994, when yields surged. Worse, long-term interest rates have risen sharply, so sharply that this week the Fed was forced (or at least encouraged) to say that it would hold interest rates steady "for a considerable period" even if growth picks up further.It is fairly clear that the Fed has been shaken by the bounce in bond yields since the spring: the 10-year rate rose from 3.2 per cent to about 4.4 per cent before steadying. But, in general, he has been praised for driving down short-term interest rates and helping the US to come through this recession in better shape than previous ones.

Or so it seems.But all policies have costs, and the cost seems to be a slower recovery than after any recession, at least since the Second World War. This has profound implications for the developed world, including Britain We have seen the limits of central bank power. Our own Bank of England is acutely aware of the dangers of any loss of authority, as its reaction to the new inflation target shows. But this is a global story, not just a UK one.For several years the Federal Reserve has appeared all-powerful.

Now it is becoming clear that it will have to hold rates low for a long time. We have known for some time that the Federal Reserve no longer had any freedom to drop interest rates further. Important drugs such as Nexium, for ulcers, and Seroquel, for schizophrenia, might find themelves starved of support. Perhaps they should be checking blood pressure back at AstraZeneca's London headquarters.m.harrison independent.co.uk.

The penny has dropped in the US. AstraZeneca cannot match its rivals' marketing muscle, and that often counts for more than the strength of clinical data. The event is a "celebration" of the launch of the company's new anti-cholesterol drug Crestor, which got the green light from US regulators on Tuesday.As a means of educating people of the dangers of high cholesterol levels, it is probably the cheapest stunt that AstraZeneca will undertake The marketing proper will be much more costly. It is pushing its new pill into a crowded market which already boasts the world's biggest selling medicine, the mighty Pfizer's Lipitor, which has sales of nearly $25m (£15.6m) a day.In the year that Crestor has been delayed by safety concerns, the growth in demand for these sorts of drugs has slowed sharply, from 11 per cent to barely 4 per cent.The more serious question is what happens to the rest of the business as AstraZeneca strains the sinews to make Crestor the blockbuster drug investors crave. The Bank of England, as we can see, reckons that the risk to growth remains on the downside while the Fed has again made plain its continued concerns about the threat of deflation de-railing the US economy. If it isn't too uncomfortable, Mr Wuffli, keep your ear to the ground and your nostrils in the air.Crestor concernsWho would work for a drug company? The lucky 5,500 employees at AstraZeneca's US headquarters in Wilmington, Delaware, will be lined up next week to have their cholesterol levels tested. The long-term case for equities remains strong but so does short-term selling pressure.