A Note on Business Cycle Accounting

Chari, Kehoe and McGrattan (2007) (CKM) show that a large class of dynamic stochastic general equilibrium (DSGE) models with various frictions and shocks is observationally equivalent to a benchmark real business cycle (RBC) model with correlated "wedges" in the RBC model's first-order conditions. The wedges in the static first-order conditions of the RBC model can be readily computed by evaluating the first-order conditions at the data and then solving for the wedges. In contrast, identification of the "investment wedge" in the RBC model's dynamic Euler equation requires the researcher to make assumptions about the expectation formation by agents in the RBC model. In particular, CKM assume that expectations are formed as if, from the perspective of the model's agents, wedges followed a vector autoregressive process of order one (VAR(1)). We show that wedges generally do not have a VAR(1) representation, implying that CKM's procedure is based on model-inconsistent expectations. We also provide an alternative, model-consistent approach to modeling expectation formation. On the former issue, we present a necessary and sufficient ``rank condition'' under which a detailed economy can be mapped into a benchmark model where wedges follow a VAR(1) process. On the latter issue, we suggest that the information set underlying the expectation formation should not only contain current wedges, but also all predetermined variables.Business Cycle Accounting; Model Consistent Expectations

The Role of Sectoral Shifts in the Great Moderation

In this paper, I study the drop of real GDP volatility which has been observed in the United States during the postwar period. This paper thoroughly estimates how much sectoral shifts contributed to this phenomenon called the Great Moderation. In a short section, Stock and Watson (2003) find that this contribution is negligible, however, their data is disaggregated only up to 10 sectors. Blanchard and Simon (2001) come to the same result. Using a new estimation method and more disaggregated data, I find that sectoral shifts contributed between 15% and 30% to the great moderation. Moreover, I find that if in the year 1949 sectoral shares had been equal to what they were in 2005, then the conditional and unconditional standard deviation of GDP growth would have been, on average, 20-25% lower in the postwar period. Finally, I find that the shift out of durable goods production has significantly stabilized real GDP growth. As a methodological contribution, I show how to use the particle filter to estimate latent covariance matrices when they follow a Wishart autoregressive process of order one. I use this in order to get, for each observation period, an estimation of the covariance matrix of the sectoral growth rates. Since real GDP growth is the sum of these sectoral growth rates weighted by the sectoral shares, it is then straightforward to use these covariance matrices to express the conditional variance of GDP growth in each period as a function of sectoral shares. Computing the unconditional variance of GDP growth as a function of sectoral shares is a bit more involved, but also quite easy using Monte Carlo simulations. My methodology to estimate covariance matrices is preferable to alternatives like estimating a multivariate GARCH model or using a Nadaraya-Watson estimator for the following reasons: The multivariate GARCH model has undesirable properties for the Monte Carlo simulations and involves estimating a large number of parameters. The Nadaraya-Watson estimator, on the other hand, does not guarantee to give positive definite covariance matrices due to the limited number of observations available for estimating the relatively big covariance matrices.Great moderation; Sectoral Shifts; Stochastic Volatility; Wishart Autoregressive Process; Particle Filter; ARCH-GARCH; Bayesian Estimation

THE ROLE OF SECTORAL SHIFTS IN THE DECLINE OF REAL GDP VOLATILITY

U.S. production has shifted from goods-producing to service-producing industries. We assess whether this shift contributed to the decline in U.S. output volatility over the period 1949-2005 and provide an estimate of its relative importance. Growth rates of GDP by industry are analyzed in a seemingly unrelated multivariate autoregression framework with time-varying innovation covariance matrices. These changing unobserved covariance matrices are modeled as a Wishart autoregressive process of order one, which results in a nonlinear state-space system. The particle filter is used to obtain estimates of the innovation covariance matrix at each point in time. Several counterfactual experiments make it possible to apportion the decline in output volatility between the shift in the sectoral composition and changes in innovations. Our main finding is that the shift into the service sector can explain about 30% of the decline in GDP's volatility, despite the fact that some sectors became even more volatile. This result is robust across a wide variety of alternative specification

Niko Kuret, Maske slovenskih pokrajin, Cankarjeva založba in ZRC SAZU, Institut za slovensko narodopisje, Ljubljana 1984, 544 str.

Additional file 1. Computational details

Mutations that affect the surface expression of TRPV6 are associated with the upregulation of serine proteases in the placenta of an infant

Recently, we reported a case of an infant with neonatal severe under-mineralizing skeletal dysplasia caused by mutations within both alleles of the TRPV6 gene. One mutation results in an in frame stop codon (R(510)stop) that leads to a truncated, nonfunctional TRPV6 channel, and the second in a point mutation (G(660)R) that, surprisingly, does not affect the Ca(2+) permeability of TRPV6. We mimicked the subunit composition of the unaffected heterozygous parent and child by coexpressing the TRPV6 G(660)R and R(510)stop mutants and combinations with wild type TRPV6. We show that both the G(660)R and R(510)stop mutant subunits are expressed and result in decreased calcium uptake, which is the result of the reduced abundancy of functional TRPV6 channels within the plasma membrane. We compared the proteomic profiles of a healthy placenta with that of the diseased infant and detected, exclusively in the latter two proteases, HTRA1 and cathepsin G. Our results implicate that the combination of the two mutant TRPV6 subunits, which are expressed in the placenta of the diseased child, is responsible for the decreased calcium uptake, which could explain the skeletal dysplasia. In addition, placental calcium deficiency also appears to be associated with an increase in the expression of proteases

Mutations That Affect the Surface Expression of TRPV6 Are Associated with the Upregulation of Serine Proteases in the Placenta of an Infant

Recently, we reported a case of an infant with neonatal severe under-mineralizing skeletal dysplasia caused by mutations within both alleles of the TRPV6 gene. One mutation results in an in frame stop codon (R510stop) that leads to a truncated, nonfunctional TRPV6 channel, and the second in a point mutation (G660R) that, surprisingly, does not affect the Ca2+ permeability of TRPV6. We mimicked the subunit composition of the unaffected heterozygous parent and child by coexpressing the TRPV6 G660R and R510stop mutants and combinations with wild type TRPV6. We show that both the G660R and R510stop mutant subunits are expressed and result in decreased calcium uptake, which is the result of the reduced abundancy of functional TRPV6 channels within the plasma membrane. We compared the proteomic profiles of a healthy placenta with that of the diseased infant and detected, exclusively in the latter two proteases, HTRA1 and cathepsin G. Our results implicate that the combination of the two mutant TRPV6 subunits, which are expressed in the placenta of the diseased child, is responsible for the decreased calcium uptake, which could explain the skeletal dysplasia. In addition, placental calcium deficiency also appears to be associated with an increase in the expression of proteases

Lineage-Specific Genome Architecture Links Enhancers and Non-coding Disease Variants to Target Gene Promoters

This is the final version of the article. It first appeared from Elsevier (Cell Press) via https://doi.org/10.1016/j.cell.2016.09.03

Los servicios en los esquemas de integración: algunas consideraciones y opciones para Centroamérica: versión provisional

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