A reassessment of Argentina´s GHG proposed target

At the time of Argentina´s greenhouse gases emissions reduction voluntary commitment, most of the articles on intensity targets had not been published. The aim of this paper is to (re)discuss briefly the proposal made by Argentina taking into account that literature. To justify the adopted target form and stringency, we compare fixed and dynamic targets in terms of the likelihood of “hot air”, the relationship between allowed emissions and GDP, the link between abatement and GDP, and outcomes´ dispersion. But, the assumptions implicit in the design of the target may change those properties. We show how the BAU scenario taken as reference and the level of emissions reduction affects targets´ design and characteristics. Finally, considering different emissions projections, we perform a comparison between allowed emissions and projected ones during the first half commitment period (2008-2010), concluding that compliance with the commitment depends on the data source used in the calculations.climate change, intensity targets, uncertainty, Argentina

Terrestrial-type planet formation: Comparing different types of initial conditions

To study the terrestrial-type planet formation during the post oligarchic growth, the initial distributions of planetary embryos and planetesimals used in N-body simulations play an important role. Most of these studies typically use ad hoc initial distributions based on theoretical and numerical studies. We analyze the formation of planetary systems without gas giants around solar-type stars focusing on the sensitivity of the results to the particular initial distributions of planetesimals and embryos. The formation of terrestrial planets in the habitable zone (HZ) and their final water contents are topics of interest. We developed two different sets of N-body simulations from the same protoplanetary disk. The first set assumes ad hoc initial distributions for embryos and planetesimals and the second set obtains these distributions from the results of a semi-analytical model which simulates the evolution of the gaseous phase of the disk. Both sets form planets in the HZ. Ad hoc initial conditions form planets in the HZ with masses from $0.66M_{\oplus}$ to $2.27M_{\oplus}$. More realistic initial conditions obtained from a semi-analytical model, form planets with masses between $1.18M_{\oplus}$ and $2.21M_{\oplus}$. Both sets form planets in the HZ with water contents between 4.5% and 39.48% by mass. Those planets with the highest water contents respect to those with the lowest, present differences regarding the sources of water supply. We suggest that the number of planets in the HZ is not sensitive to the particular initial distribution of embryos and planetesimals and thus, the results are globally similar between both sets. However, the main differences are associated to the accretion history of the planets in the HZ. These discrepancies have a direct impact in the accretion of water-rich material and in the physical characteristics of the resulting planets.Comment: Accepted for publication in Astronomy and Astrophysics, 13 pages, 9 figure

"Pensar la guerra, Clausewitz": la interpretación aroniana del Vom Kriege

For the last two centuries “Vom Kriege” has been used to justify two different kinds of totalitarianisms: Marxism-Leninism and Nazism. However, during the 1950s Liberal thinking also made use of that work. In line with Liberal thinking, Raymond Aron’s “Penser la Guerre, Clausewitz” presents Clausewitz’s work as moderate and liberal and underplays its totalitarian connections

Los determinantes de pasarse de las AFJP al sistema jubilatorio de reparto

Previo a la reciente creación del Sistema Integrado Previsional Argentino (SIPA), la Reforma del Sistema Previsional en 2007 representó el primer cambio significativo desde el año 1994. Por primera vez los trabajadores cuyas contribuciones se dirigían al régimen privado de capitalización, pudieron libremente optar por pasarse al régimen de público de reparto. Este trabajo intenta analizar las características distintivas de aquellos que optaron por cambiarse al régimen estatal a la vez que se busca indagar si la conducta de estos individuos se encuentra en línea con la maximización de ingresos de un “trabajador simulado”. El análisis se completa con la estimación de probabilidades de traspaso de individuos con diferentes características.

Dynamical evolution of escaped plutinos, another source of Centaurs

It was shown in previous works the existence of weakly chaotic orbits in the plutino population that diffuse very slowly. These orbits correspond to long-term plutino escapers and then represent the plutinos that are escaping from the resonance at present. In this paper we perform numerical simulations in order to explore the dynamical evolution of plutinos recently escaped from the resonance. The numerical simulations were divided in two parts. In the first one we evolved 20,000 test particles in the resonance in order to detect and select the long-term escapers. In the second one, we numerically integrate the selected escaped plutinos in order to study their dynamical post escaped behavior. Our main results include the characterization of the routes of escape of plutinos and their evolution in the Centaur zone. We obtained a present rate of escape of plutinos between 1 and 10 every 10 years. The escaped plutinos have a mean lifetime in the Centaur zone of 108 Myr and their contribution to the Centaur population would be a fraction of less than 6 % of the total Centaur population. In this way, escaped plutinos would be a secondary source of Centaurs.Comment: Accepted for publication in A&

Collisional and dynamical evolution of the main belt and NEA population

Aims. In this paper, we analyze the collisional evolution of the Main Belt and NEA population taking into account the major dynamical features present in both populations. Methods. To do this, we divide the asteroid belt into three semimajor axis zones, whose boundaries are given by the V6, secular resonance, and the 3:1, 5:2 and 2:1 mean motion resonances with Jupiter, treating them as strong sources of dynamical removal. We also consider the action of the Yarkovsky effect and diffusive resonances as mechanisms of mass depletion. This treatment allows us to calculate the direct collisional injection into the powerful resonances, to study the collisional exchange of mass between the different regions of the Main Belt and to analyze the provenance of the NEA objects. Results. Our model is in agreement with the major observational constraints associated with the Main Belt and NEA populations, such as their size distributions, the collisional history of Vesta, the number of large asteroid families and the cosmic-ray exposure (CRE) ages of meteorites. We find that none of the dynamical and collisional mechanisms included in our treatment are able to mix material between the three studied main belt regions, since more than 99% of the final mass of every ring of our model of the Main Belt is represented by primordial material. In addition, our results supports that the Yarkovsky effect is the most important process that removes material from the asteroid Main Belt, rather than collisional injection into the major resonances. With regards to the provenance of the NEAs, our work shows that ∼94% of the NEA population comes from the region inside the 5:2 mean motion resonance.Facultad de Ciencias Astronómicas y Geofísica