12,211 research outputs found
Optimal Oil Taxation in a Small Open Economy
The international oil market has been very volatile over the past three decades. In industrialized economies, especially in Europe, taxes represent a large fraction of oil prices and governments do not seem to react to oil price shocks by using oil taxes strategically. The aim of this paper is to analyze optimal oil taxation in a dynamic stochastic general equilibrium model of a small open economy that imports oil. We obtain that in general it is not optimal to distort the oil price paid by firms with taxes. Extending the model in several ways this result could be reversed depending on environmental considerations and available fiscal instruments.Optimal oil taxation, general equilibrium, small open economies
The extremely asymmetric radio structure of the z=3.1 radio galaxy B3 J2330+3927
We report on 1.7 and 5.0 GHz observations of the z=3.087 radio galaxy B3
J2330+3927, using the Very Long Baseline Array (VLBA), and archival 1.4 and 8.4
GHz Very Large Array (VLA) data. Our VLBA data identify a compact, flat
spectrum (\alpha_{1.7 GHz}^{5 GHz} = -0.2 +/- 0.1; S_\nu ~ \nu^\alpha) radio
component as the core. The VLA images show that the fraction of core emission
is very large (f_c \approx 0.5 at 8.4 GHz), and reveal a previously undetected,
very faint counterjet, implying a radio lobe flux density ratio R >= 11 and a
radio lobe distance ratio Q \approx 1.9. Those values are much more common in
quasars than in radio galaxies, but the optical/near-IR spectra show a clear
type II AGN for B3 J2330+3927, confirming that it is indeed a radio galaxy.
Unlike all other radio galaxies, the bright Ly-\alpha emitting gas is located
towards the furthest radio arm. We argue against environmental and relativistic
beaming effects being the cause of the observed asymmetry, and suggest this
source has intrinsically asymmetric radio jets. If this is the case, B3
J2330+3927 is the first example of such a source at high redshift, and seems to
be difficult to reconcile with the unified model, which explains the
differences between quasars and radio galaxies as being due to orientation
effects.Comment: 6 pages, 3 figures, to appear as a Letter to MNRA
The appreciation of the Art of wallpaper in one of the last royal manufactures of the Old Spanish Regime
Reseña de: Rose-de Viejo, Isadora, La Real Fábrica de Papeles Pintados de Madrid (1786-1836), Madrid, Cátedra, 2015, 240 p
Goya y el redescubrimiento del Arte de pintar para la creación de tapices
Reseña de: Goya en Madrid. Cartones para tapices 1775-1794, catálogo de exposición, Madrid, Museo Nacional del Prado, 2014, 320 pp
Policies and Motivations for the CO2 Valorization through the Sabatier Reaction Using Structured Catalysts. A Review of the Most Recent Advances
The current scenario where the effects of global warming are more and more evident, has motivated different initiatives for facing this, such as the creation of global policies with a clear environmental guideline. Within these policies, the control of Greenhouse Gase (GHG) emissions has been defined as mandatory, but for carrying out this, a smart strategy is proposed. This is the application of a circular economy model, which seeks to minimize the generation of waste and maximize the efficient use of resources. From this point of view, CO2 recycling is an alternative to reduce emissions to the atmosphere, and we need to look for new business models which valorization this compound which now must be considered as a renewable carbon source. This has renewed the interest in known processes for the chemical transformation of CO2 but that have not been applied at industrial level because they do not offer evident profitability. For example, the methane produced in the Sabatier reaction has a great potential for application, but this depends on the existence of a sustainable supply of hydrogen and a greater efficiency during the process that allows maximizing energy efficiency and thermal control to maximize the methane yield. Regarding energy efficiency and thermal control of the process, the use of structured reactors is an appropriate strategy. The evolution of new technologies, such as 3D printing, and the consolidation of knowledge in the structing of catalysts has enabled the use of these reactors to develop a wide range of possibilities in the field. In this sense, the present review presents a brief description of the main policies that have motivated the transition to a circular economy model and within this, to CO2 recycling. This allows understanding, why efforts are being focused on the development of different reactions for CO2 valorization. Special attention to the case of the Sabatier reaction and in the application of structured reactors for such process is paid
Magnitud, composición y patrones espaciotemporales de la mortalidad de vertebrados en las carreteras a escala regional
Although roadkill studies on a large scale are challenging, they can provide valuable information to assess the impact of road traffic on animal populations. Over 22 months (between July 2009–June 2010, and April 2011–March 2012) we surveyed 45 road sections of 10 km within a global biodiversity hotspot in Andalusia (87,000 km2), in southern Spain. We divided the region into five ecoregions differing in environmental conditions and landscape characteristics and recorded the relative magnitude, composition and spatiotemporal patterns of vertebrate (birds, mammal, amphibians, and reptiles) mortality. We used roadkill data from monthly surveys of road stretches with different speed limits, traffic volume, road design, and adjacent landscape composition. Roadkills varied over time and were not randomly distributed across ecoregions and road types. Overall, the groups most frequently encountered were mammals (54.4% of total roadkills) and birds (36.2%). Mortality rates in these two groups were higher on highways than on national or local roads, whereas those of amphibians (4.6%) and reptiles (4.3%) did not differ between road types. Except for mammals, the observed variation in vertebrate roadkills across ecoregions reflects the patterns of species richness previously described in the literature. Roadkills were concentrated over relatively short periods and this pattern was repeated over study periods and for all vertebrate classes. Our findings provide baseline information about road types, time periods and taxa with a higher probability of roadkills across an extensive region. These data represent an essential step towards the future implementation of broad–scale mitigation measures.A pesar de que los estudios a gran escala sobre mortalidad de animales en las carreteras son complejos, pueden aportar información valiosa para evaluar la incidencia del tráfico en las poblaciones de animales. Durante 22 meses (entre julio de 2009 y junio de 2010 y entre abril de 2011 y marzo de 2012), muestreamos 45 tramos de carretera de 10 km de longitud distribuidos en una zona con una gran diversidad en la región de Andalucía (87.000 km2), en el sur de España. La región se dividió en cinco ecorregiones con diferentes condiciones ambientales y características del paisaje, y se analizaron la magnitud, la composición y los patrones espaciotemporales de la mortalidad de vertebrados (aves, mamíferos, anfibios y reptiles). Usamos datos de atropellos obtenidos durante muestreos mensuales en tramos de carretera con diferentes límite de velocidad, volumen de tráfico, diseño de la carretera y composición del paisaje adyacente. Los animales atropellados fueron distintos en el tiempo y no se distribuyeron aleatoriamente entre ecorregiones ni entre tipos de carretera. En total, los grupos que se encontraron con mayor frecuencia fueron los mamíferos (el 54,4% de los atropellos registrados) y las aves (el 36,2%). La tasa de mortalidad observada en estos dos grupos fue mayor en autopistas que en carreteras nacionales o locales, mientras que la mortalidad de anfibios (el 4,6%) y de reptiles (el 4,3%) no presentó diferencias entre tipos de carretera. A excepción de los mamíferos, la variación observada de la mortalidad en las carreteras entre las diferentes ecorregiones refleja los patrones de riqueza de especies descritos en las publicaciones científicas. Los atropellos se concentraron en períodos de tiempo relativamente cortos y este patrón se repitió en las dos temporadas de estudio y con respecto a todas las clases de vertebrados. Nuestros resultados proporcionan información de referencia sobre los tipos de carretera, los períodos de tiempo y los taxones con una mayor probabilidad de morir por atropello en una extensa región, lo que supone un paso esencial para la implementación de medidas de mitigación a gran escala.Fil: Canal Piña, David. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Ciencias de la Tierra y Ambientales de La Pampa. Universidad Nacional de La Pampa. Facultad de Ciencias Exactas y Naturales. Instituto de Ciencias de la Tierra y Ambientales de La Pampa; Argentina. Consejo Superior de Investigaciones Científicas; EspañaFil: Camacho, Carlos. Consejo Superior de Investigaciones Científicas; EspañaFil: Martín, Beatriz. Complejo Huerta Grande; EspañaFil: de Lucas, Manuela. Consejo Superior de Investigaciones Científicas; EspañaFil: Ferrer, Miguel. Consejo Superior de Investigaciones Científicas; Españ
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