111 research outputs found

    Non-linearities and unit roots in G7 macroeconomic variables

    Get PDF
    We carry out a meta-analysis on the frequency of unit-roots in macroeconomic time series with a dataset covering 249 variables for the G7 countries. We use linear tests and the three popular non-linear tests (TAR, ESTAR and Markov Switching). In general, the evidence in favour of the random walk hypothesis is weaker than in previous studies. This evidence against unit roots is stronger for real and nominal asset prices. Our results show that rejection of the null of a unit root in the macro dataset is substantially higher for non-linear than linear models. Finally, the results from a Monte Carlo experiment show that rejection frequencies are very close to the nominal size of the test when the DGP is a linear unit root process. This leads us to reject the hypothesis that overfitting deterministic components explains the higher rejection frequencies of nonlinear tests

    The endogeneity of the natural rate of growth

    Full text link

    The evolution of the universe from noncompact Kaluza-Klein theory

    Full text link
    We develope a 5D mechanism inspired in the Campbell's theorem, to explain the (neutral scalar field governed) evolution of the universe from a initially inflationary expansion that has a change of phase towards a decelerated expansion and thereinafter evolves towards the present day observed celerated (quintessential) expansion.Comment: version accepted in Eur. Phys. J.

    Extra force and extra mass from noncompact Kaluza-Klein theory in a cosmological model

    Full text link
    Using the Hamilton-Jacobi formalism, we study extra force and extra mass in a recently introduced noncompact Kaluza-Klein cosmological model. We examine the inertial 4D mass m0m_0 of the inflaton field on a 4D FRW bulk in two examples. We find that m0m_0 has a geometrical origin and antigravitational effects on a non inertial 4D bulk should be a consequence of the motion of the fifth coordinate with respect to the 4D bulk.Comment: final version to be published in EPJ

    Origin of FRW cosmology in slow-roll inflation from noncompact Kaluza-Klein theory

    Full text link
    Using a recently introduced formalism we discuss slow-roll inflaton from Kaluza-Klein theory without the cylinder condition. In particular, some examples corresponding to polynomic and hyperbolic Ď•\phi-potentials are studied. We find that the evolution of the fifth coordinate should be determinant for both, the evolution of the early inflationary universe and the quantum fluctuations.Comment: (final version) to be published in EPJ

    Scale invariant scalar metric fluctuations during inflation: non-perturbative formalism from a 5D vacuum

    Full text link
    We extend to 5D an approach of a 4D non-perturbative formalism to study scalar metric fluctuations of a 5D Riemann-flat de Sitter background metric. In contrast with the results obtained in 4D, the spectrum of cosmological scalar metric fluctuations during inflation can be scale invariant and the background inflaton field can take sub-Planckian values.Comment: final version to be published in Eur. Phys. J.

    Occupational choice of return migrants in Moldova

    Get PDF
    This paper analyzes the occupational choice of return migrants. Using the survey data on different aspects of migration in Moldova, we find that those who stayed illegally in the host country tend to go into wage employment on return to the home country. We also show that relatively better educated migrants tend not to be in formal employment (i.e., appear not to participate in the labor market), whereas those with relatively lower skills or who obtained a worse-than-expected outcome in the host country are more likely to be wage employed in the home country on return. We offer an economic analysis of these paradoxical results

    Seminal magnetic fields from Inflato-electromagnetic Inflation

    Full text link
    We extend some previous attempts to explain the origin and evolution of primordial magnetic fields during inflation induced from a 5D vacuum. We show that the usual quantum fluctuations of a generalized 5D electromagnetic field cannot provide us with the desired magnetic seeds. We show that special fields without propagation on the extra non-compact dimension are needed to arrive to appreciable magnetic strengths. We also identify a new magnetic tensor field BijB_{ij} in this kind of extra dimensional theories. Our results are in very good agreement with observational requirements, in particular from TeV Blazars and CMB radiation limits we obtain that primordial cosmological magnetic fields should be close scale invariance.Comment: Improved version. arXiv admin note: text overlap with arXiv:1007.3891 by other author
    • …
    corecore