On the sources of the Great Moderation

The remarkable decline in macroeconomic volatility experienced by the U.S. economy since the mid-80s (the so-called Great Moderation) has been accompanied by large changes in the patterns of comovements among output, hours and labor productivity. Those changes are reflected in both conditional and unconditional second moments as well as in the impulse responses to identified shocks. That evidencepoints to structural change, as opposed to just good luck, as an explanation for the Great Moderation. We use a simple macro model to suggest some of the immediate sources which are likely to be behindthe observed changes.

Do expectations matter? The Great Moderation revisited

We examine the role of expectations in the Great Moderation episode. We derive theoretical restrictions in a New-Keynesian model and test them using measures of expectations obtained from survey data, the Greenbook and bond markets. Expectations explain the dynamics of inflation and of interest rates but their importance is roughly unchanged over time. Systems with and without expectations display similar reduced form characteristics. Including or excluding expectations hardly changes the economic explanation of the Great Moderation. Results are robust to changes in the structure of the empirical model.

A burst of segmental duplications in the genome of the African great ape ancestor

It is generally accepted that the extent of phenotypic change between human and great apes is dissonant with the rate of molecular change. Between these two groups, proteins are virtually identical, cytogenetically there are few rearrangements that distinguish ape-human chromosomes, and rates of single-base-pair change and retrotransposon activity have slowed particularly within hominid lineages when compared to rodents or monkeys. Studies of gene family evolution indicate that gene loss and gain are enriched within the primate lineage. Here, we perform a systematic analysis of duplication content of four primate genomes (macaque, orang-utan, chimpanzee and human) in an effort to understand the pattern and rates of genomic duplication during hominid evolution. We find that the ancestral branch leading to human and African great apes shows the most significant increase in duplication activity both in terms of base pairs and in terms of events. This duplication acceleration within the ancestral species is significant when compared to lineage-specific rate estimates even after accounting for copy-number polymorphism and homoplasy. We discover striking examples of recurrent and independent gene-containing duplications within the gorilla and chimpanzee that are absent in the human lineage. Our results suggest that the evolutionary properties of copy-number mutation differ significantly from other forms of genetic mutation and, in contrast to the hominid slowdown of single-base-pair mutations, there has been a genomic burst of duplication activity at this period during human evolution.

The great diversification and its undoing

We investigate the hypothesis that macroeconomic fluctuations are primitively theresults of many microeconomic shocks, and show that it has significant explanatorypower for the evolution of macroeconomic volatility. We define ?fundamental? volatilityas the volatility that would arise from an economy made entirely of idiosyncratic microeconomicshocks, occurring primitively at the level of sectors or firms. In its empiricalconstruction, motivated by a simple model, the sales share of different sectors vary overtime (in a way we directly measure), while the volatility of those sectors remains constant.We find that fundamental volatility accounts for the swings in macroeconomicvolatility in the US and the other major world economies in the past half century. Itaccounts for the ?great moderation? and its undoing. Controlling for our measure offundamental volatility, there is no break in output volatility. The initial great moderationis due to a decreasing share of manufacturing between 1975 and 1985. The recentrise of macroeconomic volatility is due to the increase of the size of the financial sector.We provide a model to think quantitatively about the large comovement generated byidiosyncratic shocks. As the origin of aggregate shocks can be traced to identifiablemicroeconomic shocks, we may better understand the origins of aggregate fluctuations.

[Archives de la Parole]. , The [Parable of] the Prodigal son : in Khariā / [Sir George Grierson], éd. ; Linguistic survey of India ; Voix parlée

[Traditions. Asie. Inde. Chotā Nāgpur]

[Archives de la Parole]. , Parable of the prodigal son in Parjé [i.e. parji], from Bastar (C.P) [i.e. Central Provinces] : dravidien, Linguistic survey of India, [Sir George] Grierson / [Sir George Grierson], éd. ; Linguistic survey of India ; [Bhima Parjā], voix

[Traditions. Asie. Inde. Madhya Pradesh. Chhattisgarh]

[Archives de la Parole]. , Parable of the prodigal son : in Kodaku, from Surguja / [Sir George Grierson], éd. ; Linguistic survey of India ; [Jūthan Koḍākū], voix

[Traditions. Asie. Inde. Madhya Pradesh. Chhattisgarh]

[Archives de la Parole]. , Parable of the prodigal son : in Hō / [Sir George Grierson], éd. ; Linguistic survey of India ; Voix parlée

[Traditions. Asie. Inde. Chotā Nāgpur]

[Archives de la Parole]. , Parable of the prodigal son : in mixed Baghelkhandi (C.P.) [i.e. Central Provinces], from Murwara / [Sir George Grierson], éd. ; Linguistic survey of India ; [Rai Bahadur Hiralal], voix

[Traditions. Asie. Inde. Madhya Pradesh. Baghelkhand]

[Archives de la Parole]. , Parable of the prodigal son : in Santali / [Sir George Grierson], éd. ; Linguistic survey of India ; Voix parlée

[Traditions. Asie. Inde. Chotā Nāgpur]

[Archives de la Parole]. , Parable of the prodigal son : in telugu, from Chanda (C.P.) [i.e. Central Provinces] / [Sir George Grierson], éd. ; Linguistic survey of India ; [Gangadhar], voix

[Traditions. Asie. Inde. Madhya Pradesh. Maharashtra]

[Archives de la Parole]. , Parable of the prodigal son : in Kurukh - Dravidien - Linguistic survey of India / [Sir George Grierson], éd. ; Linguistic survey of India ; Voix parlée, homme

[Traditions. Asie. Inde. Chotā Nāgpur]

[Archives de la Parole]. , Parable of the prodigal son in Chhattīsgaṛhī Hindī / [Sir George Grierson], éd. ; Linguistic survey of India ; [Mr. Ramanand, B.A., LL.B], voix

[Traditions. Asie. Inde. Madhya Pradesh. Chhattisgarh]

[Archives de la Parole]. , Parable of the prodigal son : in Gondi, from Bastar (C.P) [i.e. Central Provinces] - Dravidien - Ling[uistic] survey of India / [Sir George Grierson], éd. ; Linguistic survey of India ; [Kesrī Gond], voix

[Traditions. Asie. Inde. Madhya Pradesh. Chhattisgarh]

[Archives de la Parole]. , Parable of the prodigal son : in Korwa, from Surguja (C.P.) [i.e. Central Provinces] / [Sir George Grierson], éd. ; Linguistic survey of India ; [Nathu Kōrwā], voix

[Traditions. Asie. Inde. Madhya Pradesh. Chhattisgarh]