This essay argues that the history of macroeconomics during the twentieth century can be divided into three epochs. Pre-1940: a period of exploration, during which all the right ingredients were developed. But also a period where confusion reigned, because of the lack of an integrated framework. From 1940 to 1980: a period during which an integrated framework was developed—from the IS-LM to dyn...

We present the first results on the analysis of the structures observed in the jet of the quasar 0836+710. We obtain the ridge lines of the jet at different epochs and several frequencies. We interpret the oscillatory structures obtained as waves that can be attached to the growth of instabilities. We explain how to derive information on the nature and origin of these structures by fitting toge...

The cosmological model best capable of fitting current observational data features two separate epochs during which the Universe is accelerating. During the earliest stages of the Universe, such acceleration is known as cosmological inflation, believed to explain the global properties of the Universe and the origin of structure. Observations of the present state of the Universe strongly suggest...