1,423 research outputs found

    A Note on the Dynamics of Persistence in US Inflation

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    Empirical research on the degree and stability of inflation persistence in the US has produced mixed results: some suggest high and unchanged persistence during the last few decades, while others argue in favor of a decline in persistence since the early 1980s. We show that post-WWII US inflation (monthly and quarterly) became highly persistent during the´Great Inflation´ period, and then switched back to a low persistence process during 1984, and has remained stationary until the present day.Inflation, Multiple change in persistence, Stationarity, Great inflation.

    On the dynamics of inflation persistence around the world

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    We study the dynamics of inflation persistence in 45 countries for the period 1960-2008. We use a nonparametric unit root test robust to nonlinearities, error distributions, structural breaks and outliers, many of them typical features of inflation data, and a test for multiple changes in persistence, which decomposes the sample information between adjacent I(0) and I(1) periods. We find that (1) With very few exceptions, inflation around the world rejects a unit root, (2) for several countries there is evidence of significant changes in persistence, (3) bursts and drops in the level of inflation and in inflation persistence tend to coincide, (4) these drops occurred during “the Great Moderation” and during the adoption of inflation targeting. We conclude that inflation is characterized by either a stationary behaviour throughout the sample, or by switches of the type I(0)-I(1)-I(0). For all countries in our sample, any indication of nonstationarity seems to be temporary.Inflation, Multiple persistence change, Stationarity, Unit root tests, Unknown direction of change, Monetary policy

    Time Series Approach to Test a Change in Inflation Persistence: The Mexican Experience.

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    When monetary policy has an explicit inflation target, observed inflation should be a stationary process. In countries where, for a variety of reasons, the determinants of inflation could lead it to follow a non-stationary process, the adoption of an inflation targeting framework should therefore induce a fundamental change in the stochastic process governing inflation. This paper studies the time series properties of Mexican inflation during 1995-2006, using recently developed techniques to detect a change in the persistence of economic time series. Consistent with the adoption of an inflation-targeting framework, the results suggest that inflation in Mexico seems to have switched from a nonstationary to a stationary process around the end of year 2000 or the beginning of 2001.Inflation, Persistence change, Stationarity, Unit root tests, Unknown direction of change

    Finite density and temperature in hybrid bag models

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    We introduce the chemical potential in a system of two-flavored massless fermions in a chiral bag by imposing boundary conditions in the Euclidean time direction. We express the fermionic mean number in terms of a functional trace involving the Green function of the boundary value problem, which is studied analytically. Numerical evaluations for the fermionic number are presented.Comment: 19 pages, 4 figure

    Distinguishing hypertension from hypertrophic cardiomyopathy as a cause of left ventricular hypertrophy

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    Distinguishing Hypertension From Hypertrophic Cardiomyopathy as aCause of Left Ventricular HypertrophyIn most hypertensive patients, left ventricular (LV) wallthickness is normal or only mildly increased (≤13 m

    Confined two-dimensional fermions at finite density

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    We introduce the chemical potential in a system of two-dimensional massless fermions, confined to a finite region, by imposing twisted boundary conditions in the Euclidean time direction. We explore in this simple model the application of functional techniques which could be used in more complicated situations.Comment: 15 pages, LaTe

    Massless fermions in a bag at finite density and temperature

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    We introduce the chemical potential in a system of massless fermions in a bag by impossing boundary conditions in the Euclidean time direction. We express the fermionic mean number in terms of a functional trace involving the Green's function of the boundary value problem, which we study analytically. Numerical evaluations are made, and an application to a simple hadron model is discussed.Comment: 14 pages, 3 figures, RevTe

    The Pleistocene Glyptodontidae Gray, 1869 (Xenarthra: Cingulata) of Colombia and some considerations about the South American Glyptodontinae

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    Until recently, one well-characterized Pleistocene genus of the subfamily Glyptodontinae (Glyptodon ca. 1.08-0.0011 My) was recognized in South America. In recent times, some authors have demonstrated, through the re-analysis of material originally classified as Glyptodon Owen and Hoplophorus Lund, the presence of a second species belonging to the North American glyptodontine Glyptotherium Osborn (ca. 58-12 ky BP), currently known from in Venezuela and Brazil. This situation implies the need for a new study, with modern taxonomical criteria, of those materials belonging to the Glyptodontinae, particularly in those territories where the knowledge of these taxa is scarce. Presented here is a new analysis of the Pleistocene Glyptodontidae from Colombia, including some taxonomic and paleobiogeographic remarks. The results show that the only reported Glyptodontidae specimens in Colombia belong to Glyptodon sp. In turn, the evidence suggests that only one single species of Glyptotherium is present in South America, currently assigned to Glyptotherium cf. Gl. cylindricum. However, a more accurate analysis is necessary to confirm or refute this taxonomic identification. To date, Glyptotherium present has been found only in an area parallel to the Caribbean Sea and the Atlantic Ocean (northern Venezuela and eastern Brazil), up to 20°S, and is always linked to lowlands. This geographic distribution agrees with the proposition of an eastern corridor during the Great American Biotic Interchange. Below this latitude, the only recorded glyptodontine corresponds to Glyptodon, which is also recorded in a strip parallel to the Cordillera de Los Andes reaching Colombia and Venezuela. Taking into account this distribution, the presence of this genus in Central America cannot be discardedAté pouco tempo, um único gênero endêmico do Pleistoceno pertencente à subfamília Glyptodontinae (Glyptodon ca. 1.08- 0.0011 Ma) era reconhecido para a América do Sul. Recentemente, alguns autores têm demonstrado, através de novas análises do material originalmente classificado como Glyptodon Owen e Hoplophorus Lund, a presença de uma segunda espécie de Glyptodontinae pertencente ao gênero norte-americano Glyptotherium (ca. 58-12 ka AP), atualmente presente na Venezuela e Brasil. Essa situação implica na necessidade de uma nova análise do material referente à Glyptodontinae, com um critério taxonômico mais moderno, especialmente em localidades onde o conhecimento desse grupo é escasso. Na presente contribuição, é apresentada uma nova análise taxonômica dos Glyptodontidae encontrados na Colômbia, incluindo algumas observações taxonômicas e paleobiogeográficas. Os resultados demonstram que o único relato de Glyptodontidae para a Colômbia pertence à Glyptodon sp. Porém, a evidência sugere que somente uma única espécie de Glyptotherium Osborn está presente na América do Sul, atualmente atribuída a Glyptotherium cf. Gl. cylindricum. Uma análise mais precisa é necessária para confirmar sua identificação taxonômica. Até agora, Glyptotherium está presente em uma faixa paralela ao Mar Caribenho e Oceano Atlântico (Norte da Venezuela e região oriental do Brasil), até 20°S, e sempre vinculado à terras baixas. Essa distribuição geográfica concorda com a proposição de um corredor oriental durante o Grande Intercâmbio Biótico Americano. Abaixo dessa latitude, o único registro de Glyptodontinae corresponde a Glyptodon, o qual também é registrado em uma faixa paralela a Cordilheira dos Andes, alcançando Colômbia e Venezuela. Levando em consideração essa distribuição, a presença desse gênero na América Central não deveria ser descartada.Fil: Zurita, Alfredo Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; ArgentinaFil: Miño Boilini, Ángel Ramón. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; ArgentinaFil: Francia, Analia. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Arenas Mosqueras, José E.. Museo Geológico Nacional José Royo y Gómez; Colombi

    Maxwell-like Lagrangians for higher spins

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    We show how implementing invariance under divergence-free gauge transformations leads to a remarkably simple Lagrangian description of massless bosons of any spin. Our construction covers both flat and (A)dS backgrounds and extends to tensors of arbitrary mixed-symmetry type. Irreducible and traceless fields produce single-particle actions, while whenever trace constraints can be dispensed with the resulting Lagrangians display the same reducible, multi-particle spectra as those emerging from the tensionless limit of free open-string field theory. For all explored options the corresponding kinetic operators take essentially the same form as in the spin-one, Maxwell case.Comment: 77 pages, revised version. Erroneous interpretation and proof of the gauge-fixing procedure for mixed-symmetry fields corrected. As a consequence, the mixed-symmetry, one-particle Lagrangians are to be complemented with conditions on the divergences of the fields; all other conclusions unchanged. Additional minor changes including references added. To appear in JHE
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