Effects of Gamma Ray Bursts in Earth Biosphere

We continue former work on the modeling of potential effects of Gamma Ray Bursts on Phanerozoic Earth. We focus on global biospheric effects of ozone depletion and show a first modeling of the spectral reduction of light by NO2 formed in the stratosphere. We also illustrate the current complexities involved in the prediction of how terrestrial ecosystems would respond to this kind of burst. We conclude that more biological field and laboratory data are needed to reach even moderate accuracy in this modelingComment: Accepted for publication in Astrophysics & Space Scienc

A model of the Universe including Dark Energy accounted for by both a Quintessence Field and a (negative) Cosmological Constant

In this work we present a model of the universe in which dark energy is modelled explicitely with both a dynamical quintessence field and a cosmological constant. Our results confirm the possibility of a future collapsing universe (for a given region of the parameter space), which is necessary for a consistent formulation of string theory and quantum field theory. We have also reproduced the measurements of modulus distance from supernovae with good accuracy.Comment: 11 pages, 4 figures, only the results for the single exponential potential are preserved. One author added. Some changes in the reference section. Submitted to Physical Review

Biological evolution of replicator systems: towards a quantitative approach

The aim of this work is to study the features of a simple replicator chemical model of the relation between kinetic stability and entropy production under the action of external perturbations. We quantitatively explore the different paths leading to evolution in a toy model where two independent replicators compete for the same substrate. To do that, the same scenario described originally by Pross (J Phys Org Chem 17:312–316, 2004) is revised and new criteria to define the kinetic stability are proposed. Our results suggest that fast replicator populations are continually favored by the effects of strong stochastic environmental fluctuations capable to determine the global population, the former assumed to be the only acting evolution force. We demonstrate that the process is continually driven by strong perturbations only, and that population crashes may be useful proxies for these catastrophic environmental fluctuations. As expected, such behavior is particularly enhanced under very large scale perturbations, suggesting a likely dynamical footprint in the recovery patterns of new species after mass extinction events in the Earth’s geological past. Furthermore, the hypothesis that natural selection always favors the faster processes may give theoretical support to different studies that claim the applicability of maximum principles like the Maximum Metabolic Flux (MMF) or Maximum Entropy Productions Principle (MEPP), seen as the main goal of biological evolution.FAPES

How do subnational governments react to shocks to revenue sources? Evidence from Argentina

Using the exogenous variability in intergovernmental transfers and hydrocarbon royalties, based on the fiscal regime that prevailed in Argentina from 1988 to 2003, we jointly estimate the effects that changes in these public revenues had on provincial public consumption and debt. When receiving a one-peso increase in intergovernmental transfers, provinces spent 32 centavos of each peso on public consumption and 43 on debt repayment. But when hydrocarbon-producing provinces received a one-peso increase in royalties, they used 75 centavos for debt repayment. These dissimilar reactions to revenue increases are robust to different specifications of the basic regressions. Finally, we provide two alternative explanations for them: the higher volatility of hydrocarbon royalties (relative to intergovernmental transfers) and the exhaustible nature of these revenues

How Do Subnational Governments React to Shocks to Different Revenue Sources? Evidence from Hydrocarbon-Producing Provinces in Argentina

Based on the fiscal regime that prevailed in Argentina from 1988 to 2003, we estimate the effects that changes in intergovernmental transfers and hydrocarbon royalties had on provincial public consumption and debt. From a one-peso increase in intergovernmental transfers, all provinces spent 76 centavos on public consumption and decreased their debt by 22 centavos. However, when hydrocarbon-producing provinces faced a one-peso increase in royalties, they saved 95 centavos. We provide evidence that the exhaustible nature of royalties may explain this saving reaction in hydrocarbon-producing provinces