10,054 research outputs found
Endogenous Cycles in Optimal Monetary Policy with a Nonlinear Phillips Curve
There is by now a large consensus in modern monetary policy. This consensus has been built upon a dynamic general equilibrium model of optimal monetary policy with sticky prices a la Calvo and forward looking behavior. In this paper we extend this standard model by introducing nonlinearity into the Phillips curve. As the linear Phillips curve may be questioned on theoretical grounds and seems not to be favoured by empirical evidence, a similar procedure has already been undertaken in a series papers over the last few years, e.g., Schaling (1999), Semmler and Zhang (2004), Nobay and Peel (2000), Tambakis (1999), and Dolado et al. (2004). However, these papers were mainly concerned with the analysis of the problem of inflation bias, by deriving an interest rate rule which is nonlinear, leaving the issues of stability and the possible existence of endogenous cycles in such a framework mostly overlooked. Under the specific form of nonlinearity proposed in our paper (which allows for both convexity and concavity and secures closed form solutions), we show that the introduction of a nonlinear Phillips curve into a fully deterministic structure of the standard model produces significant changes to the major conclusions regarding stability and the efficiency of monetary policy in the standard model. We should emphasize the following main results: (i) instead of a unique fixed point we end up with multiple equilibria; (ii) instead of saddle--path stability, for different sets of parameter values we may have saddle stability, totally unstable and chaotic fixed points (endogenous cycles); (iii) for certain degrees of convexity and/or concavity of the Phillips curve, where endogenous fluctuations arise, one is able to encounter various results that seem interesting. Firstly, when the Central Bank pays attention essentially to inflation targeting, the inflation rate may have a lower mean and is certainly less volatile; secondly, for changes in the degree of price stickiness the results are not are clear cut as in the previous case, however, we can also observe that when such stickiness is high the inflation rate tends to display a somewhat larger mean and also higher volatility; and thirdly, it shows that the target values for inflation and the output gap (π^,x^), both crucially affect the dynamics of the economy in terms of average values and volatility of the endogenous variables --- e.g., the higher the target value of the output gap chosen by the Central Bank, the higher is the inflation rate and its volatility --- while in the linear case only the π^ does so (obviously, only affecting in this case the level of the endogenous variables). Moreover, the existence of endogenous cycles due to chaotic motion may raise serious questions about whether the old dictum of monetary policy (that the Central Bank should conduct policy with discretion instead of commitment) is not still very much in the business of monetary policy.Optimal monetary policy, Interest Rate Rules, Nonlinear Phillips Curve, Endogenous Fluctuations and Stabilization
A low-energy effective Yang-Mills theory for quark and gluon confinement
We derive a gauge-invariant low-energy effective model of the Yang-Mills
theory. We find that the effective gluon propagator belongs to the
Gribov-Stingl type and agrees with it when a mass term which breaks nilpotency
of the BRST symmetry is included. We show that the effective model with gluon
propagator of the Gribov-Stingl type exhibits both quark and gluon confinement:
the Wilson loop average has the area law and the Schwinger function violates
reflection positivity. However, we argue that both quark and gluon confinement
can be obtained even in the absence of such a mass term.Comment: 5 pages, no figures; accepted for publication in Physical Review D
(Rapid Communication
Does economic policy uncertainty impact inflation?
Using the monthly economic policy uncertainty (EPU) index of Baker et al. (2016), we examine its impact on inflation rate in the UK over the period from 1998 to 2020. We adopt a vector autoregressive (VAR) model and generate impulse response functions. To ensure that the identified shocks will be uncorrelated, based on economic theoretical considerations, we employed Cholesky restrictions. The results show that a positive innovation in EPU index leads to a weakening of the real exchange rate and unemployment rate and at the same time a rise in inflation rate. The broad implication of the present research is that under economic policy uncertainty shocks, inflation and unemployment rate respond in accordance with the effects described by the economic theory and the Phillips curve, which emphasizes that there is a trade-off between inflation and unemployment.info:eu-repo/semantics/publishedVersio
Contribution of beta1- and beta2-adrenergic receptors to cochlear function
Sympathetic innervation is heavily present in the cochlea. However, its role in the development and maintenance of normal hearing remains debatable. Beta1-adrenergic receptors 1 (beta1-ARs) and beta2-adrenergic receptors (beta2-ARs) are two types of receptors that are stimulated by the sympathetic nervous system and are expressed by many cochlear cell types. In this study, we have analyzed the functional consequences of the lack of beta-ARs in the cochlea. We have first evaluated hearing thresholds using auditory brainstem response and distortion product otoacoustic emissions in young and aged knockout mice lacking beta1-ARs, beta2-ARs, or both beta1-ARs and beta2-ARs. Secondly, we tested the sensitivity of these mice to acoustic overexposure.
Hearing tests revealed similar normal thresholds in all beta- adrenergic receptors mice when compared to age matched wild type controls. When exposed to noise mice lacking beta1- but not beta2- AR exhibited a subtle protection of hearing thresholds at the low frequencies only. These results suggest that despite being expressed by many cochlear cell types these beta-ARs are not playing a crucial role in hearing development and maintenance
Supersymmetrization of the Radiation Damping
We construct a supersymmetrized version of the model to the radiation damping
\cite{03} introduced by the present authors \cite{ACWF}. We dicuss its
symmetries and the corresponding conserved Noether charges. It is shown this
supersymmetric version provides a supersymmetric generalization of the Galilei
algebra obtained in \cite{ACWF}. We have shown that the supersymmetric action
can be splited into dynamically independent external and internal sectors.Comment: 9 page
Strategies for Prevention of Pertussis
Introdução: Nos Ăşltimos 30 anos, em vários paĂses, tem sido relatado um aumento da incidĂŞncia de tosse convulsa, sobretudo
em adolescentes e adultos, apesar das altas taxas de cobertura de imunização primária.
Objectivos: Rever aspectos da epidemiologia da tosse convulsa, descrever algumas estratégias de controlo, com ênfase nas que
incluem a utilização de vacinas com menores quantidades do toxóide diftérico e de alguns componentes pertussis (dTpa), e a
avaliação da eficácia e efectividade destas vacinas.
MĂ©todos: Selecção de artigos relevantes, atravĂ©s da base de dados PubMed e sĂtios de acesso livre da internet, publicados
entre 1991 e 2011.
Resultados: As alterações do padrĂŁo epidemiolĂłgico sĂŁo atribuĂdas,
principalmente, à diminuição da imunidade ao longo dos anos, após a vacinação ou infecção natural. Os adolescentes e adultos foram identificados como importantes fontes de transmissão da doença para lactentes muito jovens que, uma vez não imunizados ou parcialmente imunizados, são mais vulneráveis
às complicações relacionadas com a doença e apresentam maior mortalidade. A vacina (dTpa), formulada para o uso em adolescentes
e adultos é segura e eficaz. A sua utilização também reduz a transmissão da tosse convulsa para os grupos etários
com alto risco de complicações.
Conclusão: A disponibilidade da dTpa oferece novas oportunidades para reduzir o impacto da tosse convulsa. A modificação das estratégias preventivas pode levar a um melhor controlo global da doença
Geometry, stochastic calculus and quantum fields in a non-commutative space-time
The algebras of non-relativistic and of classical mechanics are unstable
algebraic structures. Their deformation towards stable structures leads,
respectively, to relativity and to quantum mechanics. Likewise, the combined
relativistic quantum mechanics algebra is also unstable. Its stabilization
requires the non-commutativity of the space-time coordinates and the existence
of a fundamental length constant. The new relativistic quantum mechanics
algebra has important consequences on the geometry of space-time, on quantum
stochastic calculus and on the construction of quantum fields. Some of these
effects are studied in this paper.Comment: 36 pages Latex, 1 eps figur
Avaliação de linhagens de arroz de terras altas no cerrado de Rondônia.
bitstream/item/79284/1/FOL-6128-0001.pd
Resposta de arroz de sequeiro à abudação mineral no cerrado de Rondônia.
O presente trabalho teve como objetivo avaliar a resposta da cultura do arroz de sequeiro a diferentes nĂveis de adubação mineral NPK, na regiĂŁo de cerrado do Estadobitstream/item/79276/1/FOL-6151-0001.pd
Noncommutative Metafluid Dynamics
In this paper we define a noncommutative (NC) Metafluid Dynamics
\cite{Marmanis}. We applied the Dirac's quantization to the Metafluid Dynamics
on NC spaces. First class constraints were found which are the same obtained in
\cite{BJP}. The gauge covariant quantization of the non-linear equations of
fields on noncommutative spaces were studied. We have found the extended
Hamiltonian which leads to equations of motion in the gauge covariant form. In
addition, we show that a particular transformation \cite{Djemai} on the usual
classical phase space (CPS) leads to the same results as of the
-deformation with . Besides, we will shown that an additional
term is introduced into the dissipative force due the NC geometry. This is an
interesting feature due to the NC nature induced into model.Comment: 11 page
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