Optimal monetary policy with state-dependent pricing

We study optimal monetary policy in a flexible state-dependent pricing framework, in which monopolistic competition and stochastic menu costs are the only distortions. We show analytically that it is optimal to commit to zero inflation in the long run. Moreover, our numerical simulations indicate that the optimal stabilization policy is "price stability". These findings represent a generalization to a state-dependent framework of the same results found for the simple Calvo model with exogenous timing of price adjustment. JEL Classification: E31optimal monetary policy, price stability, state-dependent pricing, stochastic menu costs

Zero Lyapunov exponents of the Hodge bundle

By the results of G. Forni and of R. Trevi\~no, the Lyapunov spectrum of the Hodge bundle over the Teichm\"uller geodesic flow on the strata of Abelian and of quadratic differentials does not contain zeroes even though for certain invariant submanifolds zero exponents are present in the Lyapunov spectrum. In all previously known examples, the zero exponents correspond to those PSL(2,R)-invariant subbundles of the real Hodge bundle for which the monodromy of the Gauss-Manin connection acts by isometries of the Hodge metric. We present an example of an arithmetic Teichm\"uller curve, for which the real Hodge bundle does not contain any PSL(2,R)-invariant, continuous subbundles, and nevertheless its spectrum of Lyapunov exponents contains zeroes. We describe the mechanism of this phenomenon; it covers the previously known situation as a particular case. Conjecturally, this is the only way zero exponents can appear in the Lyapunov spectrum of the Hodge bundle for any PSL(2,R)-invariant probability measure.Comment: 47 pages, 10 figures. Final version (based on the referee's report). A slightly shorter version of this article will appear in Commentarii Mathematici Helvetici. A pdf file containing a copy of the Mathematica routine "FMZ3-Zariski-numerics_det1.nb" is available at this link here: http://w3.impa.br/~cmateus/files/FMZ3-Zariski-numerics_det1.pd

Optimal monetary policy with state-dependent pricing

Estudiamos la política monetaria óptima desde una perspectiva atemporal en un modelo general de fijación de precios dependiente del estado (state-dependent pricing). Las empresas tienen poder monopolístico y están sujetas a perturbaciones idiosincráticas a sus costes de menú. Encontramos que, bajo preferencias iso-elásticas y en ausencia de gasto público, la estabilidad estricta de precios es óptima tanto en el largo plazo como en respuesta a perturbaciones agregadas. La clave de este resultado es una propiedad «envolvente»: con inflación cero, un incremento marginal en la tasa de inflación no tiene ningún efecto sobre el beneficio de las empresas y por tanto tampoco sobre la frecuencia de ajuste de los precios. Ofrecemos una solución analítica que no requiere de aproximaciones locales ni de la eficiencia del estado estacionarioWe study optimal monetary policy from the timeless perspective in a general statedependent pricing framework. Firms are monopolistic competitors and are subject to idiosyncratic menu cost shocks. We fi nd that, under isoelastic preferences and no government spending, strict price stability is optimal both in the long run and in response to aggregate shocks. Key to this finding is an “envelope” property: at zero inf ation, a marginal increase in the rate of inf ation has no effect on f rms’ profits and therefore has no effect on the rate of price adjustment. We offer an analytic solution which does not rely on local approximation or efficiency of the steady-stat

Ninety-day oral toxicity studies on two genetically modified maize MON810 varieties in Wistar Han RCC rats (EU 7th Framework Programme project GRACE)

The GMO Risk Assessment and Communication of Evidence (GRACE; www.grace-fp7.eu) project is funded by the European Commission within the 7th Framework Programme. A key objective of GRACE is to conduct 90-day animal feeding trials, animal studies with an extended time frame as well as analytical, in vitro and in silico studies on genetically modified (GM) maize in order to comparatively evaluate their use in GM plant risk assessment. In the present study, the results of two 90-day feeding trials with two different GM maize MON810 varieties, their near-isogenic non-GM varieties and four additional conventional maize varieties are presented. The feeding trials were performed by taking into account the guidance for such studies published by the EFSA Scientific Committee in 2011 and the OECD Test Guideline 408. The results obtained show that the MON810 maize at a level of up to 33 % in the diet did not induce adverse effects in male and female Wistar Han RCC rats after subchronic exposure, independently of the two different genetic backgrounds of the event

Synchronization of Heteroclinic Circuits Through Learning in Chains of Neural Motifs

The synchronization of oscillatory activity in networks of neural networks is usually implemented through coupling the state variables describing neuronal dynamics. In this study we discuss another but complementary mechanism based on a learning process with memory. A driver network motif, acting as a teacher, exhibits winner-less competition (WLC) dynamics, while a driven motif, a learner, tunes its internal couplings according to the oscillations observed in the teacher. We show that under appropriate training the learner motif can dynamically copy the coupling pattern of the teacher and thus synchronize oscillations with the teacher. Then, we demonstrate that the replication of the WLC dynamics occurs for intermediate memory lengths only. In a unidirectional chain of N motifs coupled through teacher-learner paradigm the time interval required for pattern replication grows linearly with the chain size, hence the learning process does not blow up and at the end we observe phase synchronized oscillations along the chain. We also show that in a learning chain closed into a ring the network motifs come to a consensus, i.e. to a state with the same connectivity pattern corresponding to the mean initial pattern averaged over all network motifs