Recent Behavior of Output, Unemployment, Wages and Prices in Colombia:What went Wrong?

At the end of the last decade, the real activity in Colombia underwent the sharpest recession of the last fifty years. We postulate a non-triangular structural VAR model(Amisano and Giannini, 1997) to describe the dynamics of output, prices, unemployment and wages during the last two decades. The evidence suggests that, in the long-run, monetary policy has been neutral to both output and unemployment while the main reasons for the increase in the latter have been the lack of credibility of monetary policy, the way in which wages are set and the increase in non-wage labor costs.Structural VAR,unemployment,monetary policy, wages, expectations

Recent macroeconomic performance in colombia: what went wrong?

Al finalizar la d�cada anterior la actividad real en Colombia experiment� la m�s aguda recesi�n de los �ltimos 50 a�os. Para explicar este fen�meno, postulamos un modelo VAR estructural no-triangular que describe la din�mica de la producci�n, los precios, el desempleo y los salarios durante las �ltimas dos d�cadas. La evidencia sugiere que, en el largo plazo, la pol�tica monetaria ha sido neutral con respecto al producto y la desempleo, mientras que la principal raz�n para el incremento de �ste �ltimo se explica por la forma en que se han determinado los salarios (formaci�n de expectativas hacia atr�s) y el incremento de los costos no salariales.structural VAR, unemployment, monetary policy, wages, nonwage labour costs, expectations

Geometric analysis of Lorentzian distance function on spacelike hypersurfaces

Some analysis on the Lorentzian distance in a spacetime with controlled sectional (or Ricci) curvatures is done. In particular, we focus on the study of the restriction of such distance to a spacelike hypersurface satisfying the Omori-Yau maximum principle. As a consequence, and under appropriate hypotheses on the (sectional or Ricci) curvatures of the ambient spacetime, we obtain sharp estimates for the mean curvature of those hypersurfaces. Moreover, we also give a suficient condition for its hyperbolicity.Comment: Final version (January 2009). To appear in the Transactions of the American Mathematical Societ

Weak Chaos in large conservative system -- Infinite-range coupled standard maps

We study, through a new perspective, a globally coupled map system that essentially interpolates between simple discrete-time nonlinear dynamics and certain long-range many-body Hamiltonian models. In particular, we exhibit relevant similarities, namely (i) the existence of long-standing quasistationary states (QSS), and (ii) the emergence of weak chaos in the thermodynamic limit, between the present model and the Hamiltonian Mean Field model, a strong candidate for a nonxtensive statistical mechanical approach.Comment: 6 pages, 2 figures. Corrected typos in equation 4. Changed caption in Fig. 1. Corrected references 2 and 6. Acknowledgements adde

Infectivity decline of an RNA plant virus by increased mutagenesis supports the lethal defection model in vivo

Lethal mutagenesis is a new antiviral therapy based on increasing the mutation rate by using mutagenic base and nucleoside analogues whose molecular mechanisms are not fully understood. Most of the research has been conducted on animal RNA viruses in cell culture and, to a lesser extent, in vivo. There is experimental evidence supporting the model of lethal defection for lethal mutagenesis of RNA viruses. In this model, viral genomes with a low degree of mutation and low specific infectivity, termed "defectors", exert an interfering activity leading to virus loss. Lethal mutagenesis of plant viruses has not been addressed yet despite being excellent in vivo model systems that develop systemic infections, undergo rapid bottlenecks and pose no ethical issues. Here, we address lethal mutagenesis in vivo of Tobacco mosaic virus (TMV), a single-stranded positive RNA virus of 6.4 Kb. Nicotiana tabacum plants cultured in vitro were treated with 25, 50 and 100 µg/ml of the base analogue 5-fluorouracil (FU) and 24 h later were inoculated with 50 lesion forming units (lfu) of TMV. We analyzed the infectivity, viral load and mutant spectra of viral populations after 5 and 10 days of treatment, as well as of populations that went 10 days of treatment followed by 21 days of ex vitro growth in the absence of FU. The results show that TMV infectivity decreases when treated with 50 and 100 µg/ml FU for 10 days. TMV mutagenized populations grown without FU reach infectivity values higher than untreated populations. Predominant mutations in FU-treated populations with decreased infectivity at 10 dpi are U→C, A→G and G→A transitions, which are expected due to the action of FU. TMV replication is not affected by FU at any dose and there are no imbalances of ribonucleotide triphosphate pools measured by HPLC. No differences in mutation frequencies and Shannon Entropies between control and FU-treated populations with declined infectivity were found. However, we did found a dose-dependent decrease of specific infectivity in FU-treated populations, but not in untreated samples, as well as dominance of molecules with a low degree of mutation. Specific infectivity recovered to control levels after 21 days of growth without the analogue. Altogether, our results suggest that TMV defector molecules mediate the decrease in TMV infectivity. This is the first report that addresses the molecular basis of lethal defection in vivo using an RNA plant virus.Junta de Andalucía (P09-CVI-5428 y P10-CVI-6561), Plan Nacional I+D+i (BFU2007-65080 BMC) y Universidad de Málaga (Plan propio

Measuring inequality and dependences between income sources with administrative data and survey data

Producción CientíficaThis paper aims at analyzing the effects of changing from survey to administrative data on inequality and its structure. Taking advantage of the Spanish Survey on Income and Living Conditions (ECV) that continued asking households for their income despite assigning them the income data provided by the Tax Agency and the Social Security administration, different analyses are carried out. By using copula functions we pay special attention to the effect on the dependences between income sources. We find a significant growth in the disposable income of households when using administrative data. The incomes of both tails of the distribution increase considerably more than middle incomes, and administrative data produce significantly lower levels of inequality. Using administrative instead of survey data also gives rise to changes in the structure of inequality by income sources, rising the contribution of capital income. Both methods of data collection also produce significant differences in the observed dependences between income sources.Economía Aplicad