Falling birth rates and world population decline: A quantitative discussion (1950-2040)

The UN data (1950-2010) and projections (both medium and low-fertility variants for 2015- 2040) show that fertility rates are already below replacement level in all continents except Africa. In this paper we develop a simple new approach for population projections based on a Improved Rate Equations (IRE) model. Population projections under the (1) Malthusian assumption, (2) an (IRE) model fitting and extrapolating from actual UN population data up to 2040, and (3) UN projections (low-fertility variant), are compared. The model fits quite well actual data and suggests a world population decline in the 21st Century. The economic, social and political consequences of this new and global circumstance would be far reachin

Glory revealed in disk-integrated photometry of Venus

Context. Reflected light from a spatially unresolved planet yields unique insight into the overall optical properties of the planet cover. Glories are optical phenomena caused by light that is backscattered within spherical droplets following a narrow distribution of sizes; they are well known on Earth as localised features above liquid clouds. Aims. Here we report the first evidence for a glory in the disk-integrated photometry of Venus and, in turn, of any planet. Methods. We used previously published phase curves of the planet that were reproduced over the full range of phase angles with model predictions based on a realistic description of the Venus atmosphere. We assumed that the optical properties of the planet as a whole can be described by a uniform and stable cloud cover, an assumption that agrees well with observational evidence. Results. We specifically show that the measured phase curves mimic the scattering properties of the Venus upper-cloud micron-sized aerosols, also at the small phase angles at which the glory occurs, and that the glory contrast is consistent with what is expected after multiple scattering of photons. In the optical, the planet appears to be brighter at phase angles of 11-13 deg than at full illumination; it undergoes a maximum dimming of up to 10 percent at phases in between. Conclusions. Glories might potentially indicate spherical droplets and, thus, extant liquid clouds in the atmospheres of exoplanets. A prospective detection will require exquisite photometry at the small planet-star separations of the glory phase angles.Comment: In press. Astronomy & Astrophysics. Letter to the Editor; 201

Multilayer hazes over Saturn’s hexagon from Cassini ISS limb images

Producción CientíficaVer abstract

El estrecho de las cuevas de La Encarnación (Caravaca)

Primer premio 2ª edición de Premios a la Elaboración de Materiales de Estudio sobre la Región de Murcia, modalidad Educación SecundariaEn la port.: IES Oróspeda-Archive

Prospects of world population decline in the near future: a short note

An article in Science (4 November 1960) proposed Friday 13 November AD 2026 as the "Doomsday" of planet Earth, a doomsday produced by the "world population" going to infinity. In that paper, a rudimentary rate equation describing the evolution of the world population with time, was approximated in such a way that a quantitative calculation produced that particular date. In this note, we give a more realistic rate equation which respects general conservation principles and we compare previous results and the results of our calculation, with actual UN data for 1960-2010 and UN medium term projections. At present there is disagreement among experts as to what can be expected for the world population in the future. Some think that the population is still growing out control, some say it will be approximating a constant level by 2050, whilst others expect it to be clearly in decline somewhere between 2050 and the end of 21st century. Our model shows conclusively that if no drastic and unexpected changes take place soon, the world population will be decreasing at an accelerated rate after 2050. Our rate equation approach is similar to that used in condensed matter physics and chemical physics to describe the evolution of a two level system under an external perturbation. The result is much more realistic than a purely exponential result as has been generally assumed in the last decades of the last centur

Evolución de los sistemas lacustres del margen ibérico de la Depresión del Ebro (sectores central y occidental) durante el Mioceno

Las facies lacustres identificadas en las distintas unidades  tectosedimentarias del margen ibérico de la Depresión del Ebro consisten principalmente en calizas micríticas, calcarenitas y yesos. El anhlisis de dichas facies y sus asociaciones permite establecer cuatro tipos de sistemas lacustres; dos de ellos responden a sistemas lacustres  carbonatados someros cuyas zonas marginales estan caracterizadas bien por el desarrollo importante de vegetación, o bien por laexistencia de depósitos con alto contenido en calcita magnesiana y por presentar calizas con pseudomorfos de yeso. El tercer tipo de sistemas consiste en lagos afectados por una fuerte dinámica de olcaje que se manifiestapor el desarrollo de ripples y estratificación cruzada hummocky en litofacies calcareníticas. Por Último se reconocen complejos de playa-lake donde se originan importantes depósitos de sulfatos. Estos sistemas lacustres se encuentran, en general, relacionados lateralmente con sistemas de abanicos aluviales, dando lugar a dispositives retrogradantes o  progradantes en relación con situaciones de actividad tectónica  decreciente o creciente respectivarnente. Se pone de manifiesto una evolución en los sistemas lacustres a lo largo del Mioceno en el sentido de dominar los complejos de playa-lake con depósitos de yeso y halita en la primera unidad y sistemas de lagos carbonatados en las unidades superiores. Esta evolución se puede interpretar en función de una tendencia general del clima hacia una mayor humedad; si bien no se puede descartar que tal evolución sea debida a la creciente afluencia de aguas de procedencia pirenaica que alcanzan progresivamente los sectores meridionales de la Cuenca del Ebro

Evolución de los sistemas lacustres del margen ibérico de la Depresión del Ebro (sectores central y occidental) durante el Mioceno

Las facies lacustres identificadas en las distintas unidades  tectosedimentarias del margen ibérico de la Depresión del Ebro consisten principalmente en calizas micríticas, calcarenitas y yesos. El anhlisis de dichas facies y sus asociaciones permite establecer cuatro tipos de sistemas lacustres; dos de ellos responden a sistemas lacustres  carbonatados someros cuyas zonas marginales estan caracterizadas bien por el desarrollo importante de vegetación, o bien por laexistencia de depósitos con alto contenido en calcita magnesiana y por presentar calizas con pseudomorfos de yeso. El tercer tipo de sistemas consiste en lagos afectados por una fuerte dinámica de olcaje que se manifiestapor el desarrollo de ripples y estratificación cruzada hummocky en litofacies calcareníticas. Por Último se reconocen complejos de playa-lake donde se originan importantes depósitos de sulfatos. Estos sistemas lacustres se encuentran, en general, relacionados lateralmente con sistemas de abanicos aluviales, dando lugar a dispositives retrogradantes o  progradantes en relación con situaciones de actividad tectónica  decreciente o creciente respectivarnente. Se pone de manifiesto una evolución en los sistemas lacustres a lo largo del Mioceno en el sentido de dominar los complejos de playa-lake con depósitos de yeso y halita en la primera unidad y sistemas de lagos carbonatados en las unidades superiores. Esta evolución se puede interpretar en función de una tendencia general del clima hacia una mayor humedad; si bien no se puede descartar que tal evolución sea debida a la creciente afluencia de aguas de procedencia pirenaica que alcanzan progresivamente los sectores meridionales de la Cuenca del Ebro

Síntesis estratigráfica del Terciario del borde Sur de la Cuenca del Ebro: unidades genéticas

In the southern margin of the Ebro Basin eigth Tectosedimentary Units (TSU) have been defined by means of the application of tectosedimentary analysis. These units are limited by sedimentary breaks which can be recognized in the whole studied area. The sedimentary breaks are genetically related to diastrophic evolution, and they are shown as angular or syntectonic unconformities at the basin margins. Each TSU has aparticular sequential evolution, generally complex, but with a similar trend in the entire area. For each unit the litologic composition, evolution, boundaries and chronostratigraphy are established. The three first units are placed in the Palaeogene, the fourth one includes the Palaeogene-Neogene boundary and the four last ones are Neogene in age. The chronostratigraphic interval of each one is, respectively: Thanetian-Bartonian, Bartonian-Priabonian, Priabonian-Lower Oligocene, Upper Oligocene-Agenian, Agenim-Middle Aragonian, Middle Aragonim-Upper Aragonian, Upper Aragonian-Upper Vallesian, and Turolian. Finally the equivalences between the Tectosedimentary Units and the cartographic units defiiied by other authors have been establised

Ontology Access in Grid Environments with WS-DAIOnt and the RDF(S) Realization

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The Semantic Web Framework: a component-based framework for the development of Semantic Web applications

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