What exactly al Qaeda is, or was, remains in dispute.

But Japan has experienced a low rate of inflation and some sustained short periods of deflation without ever producing a downward price spiral.

Exceptional periods sometimes create exceptional leaders.

Because transitions are dangerous times.

Very, very rare were the short intervals of quiet.

Our power supply has disappeared completely for long periods.

Historians can make a credible case that periods of maximalist over commitment have done more damage to America s place in the world than periods of retrenchment.

All of the remaining thorium isotopes have half lives that are less than thirty days and the majority of these have half lives that are less than ten minutes.

Over periods of several years, our models do better.

Post revolutionary periods, however, allow for more variety.

Quiet periods of a few days have alternated with almost continuous Strombolian eruptions since then.

Food could have been transported by rail within British India to save many starving people, but the British believed in a hands off, laissez faire policy.

The economy grew faster in good phases, and slumped more sharply in downturns.

When monsoons failed, millions of Indians faced imminent death.

Somebody goes to school, somebody does not.

This is all the more true in times of rapid fundamental change, as is occurring in China now.

Over some time periods, as if in a stand by or idling mode, the bots tweeted inspirational quotes or other content randomly lifted from the web.

Such periods always follow revolutions and times of far reaching change.

Central banks are better at restraining markets irrational exuberance in a bubble restricting the availability of credit or raising interest rates to rein in the economy than at promoting investment in a recession.

Such an approach should seek to protect economies from the destabilizing impacts of politically motivated policy changes, without impeding governments ability to correct dangerous imbalances. Officials must be at least as vigilant about reducing expenditure and withdrawing stimulus measures during periods of growth as they are inclined to introduce such policies during downturns.

Officials must be at least as vigilant about reducing expenditure and withdrawing stimulus measures during periods of growth as they are inclined to introduce such policies during downturns.

Some people believe in God and other people don't.

In any case, even if firms are cash rich, they do not typically expand investment during periods when consumption is slowing.

Everything can be measured before Wounded Knee and after.

The existing institutions were looking increasingly irrelevant in normal times, and ineffective in times of crisis.

Clearly, periods of global growth are almost always characterized by symbiotic imbalances.

Extended periods without new data facilitate indeed, foster the unrestrained growth of speculative theory bubbles.

But these distortions did not prevent unbalanced systems from enduring for long periods.

While such reserve accumulations help protect countries, in certain periods they reduce global aggregate demand.

This vacuum may encourage, as in previous historical periods, the ambitious and the aggressive to seek their own advantage.

Moreover, low inflation and periods of deflation did not prevent real incomes from rising in Japan.

At places, however, and especially in the rainy season, the streams unite into one broad fast flowing river.

Some died in prison.

Some people believe that.

Some were crying, some were yelling.

Some people cry, some people beg.

Some are good, some aren't.

But periods of global economic expansion have virtually always been characterized by symbiotic imbalances.

The bilateral relationship has been rocky ever since, alternating between periods of friction and conciliation.

They should be the major source of IMF financing as well, replacing quota subscriptions or lending to the Fund by member countries (potentially making the IMF a purely SDR based institution, as proposed decades ago by the late IMF economist Jacques Polak).

That is, SDRs could be created during global recessions and withdrawn during booms.

Some people like sports, and others don't.

Long stretches of military rule, with its emphasis on command and control, has left policymaking in Pakistan highly centralized.

How can one compare cost of living indices in different periods when new goods are constantly upending traditional consumption models?

Some economists certainly think so.