Participación vegetal en la construcción de los sistemas dunares litorales de Mallorca

[Resumen] Se establecen las relaciones entre la zonación vegetal y las áreas geomorfológicas de los sistemas dunares litorales de la isla de Mallorca. Para ello, se clasifican dichos sistemas en cuatro categorías en base a criterios morfológicos y de vegetación y se analiza la situación actual en cada uno de ellos, definiendose el papel que juega la vegetación en su arquitectura..[Abstract] The relationship between plant zonation and geomorphological areas have been studied in the coastal dunar systems of the island of Mallorca. Trough a four type classification based in vegetation and morphological criteria we point out their state of conservation and the role of the vegetation in their build-up

The central parsecs of M87: jet emission and an elusive accretion disc

We present the first simultaneous spectral energy distribution (SED) of M87 core at a scale of 0.4 arcsec ($\sim 32\, \rm{pc}$) across the electromagnetic spectrum. Two separate, quiescent, and active states are sampled that are characterized by a similar featureless SED of power-law form, and that are thus remarkably different from that of a canonical active galactic nuclei (AGN) or a radiatively inefficient accretion source. We show that the emission from a jet gives an excellent representation of the core of M87 core covering ten orders of magnitude in frequency for both the active and the quiescent phases. The inferred total jet power is, however, one to two orders of magnitude lower than the jet mechanical power reported in the literature. The maximum luminosity of a thin accretion disc allowed by the data yields an accretion rate of $< 6 \times 10^{-5}\, \rm{M_\odot \, yr^{-1}}$, assuming 10% efficiency. This power suffices to explain M87 radiative luminosity at the jet-frame, it is however two to three order of magnitude below that required to account for the jet's kinetic power. The simplest explanation is variability, which requires the core power of M87 to have been two to three orders of magnitude higher in the last 200 yr. Alternatively, an extra source of power may derive from black hole spin. Based on the strict upper limit on the accretion rate, such spin power extraction requires an efficiency an order of magnitude higher than predicted from magnetohydrodynamic simulations, currently in the few hundred per cent range.Comment: 18 pages, 6 figures. Accepted for publication in MNRA

Análisis y causas del retroceso de la línea de costa del arenal de Sa Ràpita (Mallorca)

[Resumen] Se han estudiado los cambios de la línea de costa en la playa del arenal de Sa Rapita (SE de la isla de Malllorca). A parte de la presión a trópica por el uso masivo de bañistas en época estival, el basculamiento producido por la construcción de un puerto deportivo en la parte occidental de la misma parece ser la causa principal de su retroceso. La fotografía aérea y el trabajo de campo han permitido elaborar una cartografía que nos muestra su retroceso desde 1968. El resultado final ha sido una acumulación en la zona más próxima al puerto del orden de 1.3 miaño y una erosión en el resto de la playa que alcanza los 0.7 miaño[Abstract] Shoreline changes in s'arenal de sa Rapita beach (SE of the Island of Mallorca) has been studied. The building of a marina at the west end of the beach seems to be the main cause of the shoreline backward movement, furthermore recreation activities in summer time. Aerial photograph and fieldwork have allowed a cartography showing the shoreline evolution since 1968. The final outcome has been a ratio of 1,3 m/year of beach acretion at the nearest zone of the harbour and 0,7 m/year of beach erosion in the rest of the beach

La vegetación en la gestión de las playas de Menorca

Una gestión sostenible a largo plazo de las playas, tanto en su consideración de espacio de ocio como en la de un hábitat de elevado interés ecológico, no puede consolidarse sin una visión general de estos ambientes que tenga en cuenta aspectos como la vegetación y la flora vascular que lo caracterizan. Este componente del medio natural tiene una función de gran importancia que va más allá de su caracterización, influyendo notablemente en su configuración geomorfológica y en su conservación. Menorca, donde concurren diversas situaciones y una elevada tipología de playas, puede servir de ejemplo ilustrativo. En este trabajo se realiza un recorrido explicativo sobre la vegetación que caracteriza estos ambientes y sobre su diferente estado de conservación en algunas playas, tanto aquellas que se han mantenido en un estado natural como las que han sufrido algún tipo de alteración o intervención antrópica destinada a su restauración. Con todo ello se obtiene una visión holística de las consecuencias de la alteración humana y permite exponer unas breves conclusiones o recomendación para una gestión sostenible.Beaches as a place of leisure or even as a valuable habitat for ecological conservation can get only a long term sustainable management when they are considered as a complex habitat, that is taking into consideration aspects like vegetation and the diversity of vascular flora. Plants are a keystone element in their characterization with a strong influence on geomorphological configuration and conservation. In Minorca occur a wide range of situations and types of beaches, thus it can serve as a case study. In this paper is shown a general explanation of the vegetation that characterizes these habitats, going from those with a nearly natural situation to other with a high degree of alteration, even that have been restored recently. Altogether shows a whole vision of human alteration consequences and allows exposing a few conclusions and recommendation for a sustainable management

Alteraciones de la superficie del cuerpo vertebral en una población medieval de Logroño (s. XI y XII)

X Congreso Nacional de Paleopatología. Univesidad Autónoma de Madrid, septiembre de 200

Los sistemas playa-duna de las Baleares

Abstract not availabl

El sistema playa-duna de Es Trenc (Bahía de Campos)

Abstract not availabl

La gestión del sistema duna-playa de s'Amarador (Parc Natural de Mondragó, SE de Mallorca)

Abstract not availabl

Quantifying Li-content for compositional tailoring of lithium ferrite ceramics

Owing to their multiple applications, lithium ferrites are relevant materials for several emerging technologies. For instance, LiFeO2 has been spotted as an alternative cathode material in Li-ion batteries, while LiFe5O8 is the lowest damping ferrite, holding promise in the field of spintronics. The Li-content in lithium ferrites has been shown to greatly affect the physical properties, and in turn, the performance of functional devices based on these materials. Despite this, lithium content is rarely accurately quantified, as a result of the low number of electrons in Li hindering its identification by means of routine materials characterization methods. In the present work, magnetic lithium ferrite powders with Li:Fe ratios of 1:1, 1:3 and 1:5 have been synthesized, successfully obtaining phase-pure materials (LiFeO2 and LiFe5O8), as well as a controlled mixture of both phases. The powders have been compacted and subsequently sintered by thermal treatment (Tmax = 1100 {\deg}C) to fabricate dense pellets which preserve the original Li:Fe ratios. Li-content on both powders and pellets has been determined by two independent methods: (i) Rutherford backscattering spectroscopy combined with nuclear reaction analysis and (ii) Rietveld analysis of powder X-ray diffraction data. With good agreement between both techniques, it has been confirmed that the Li:Fe ratios employed in the synthesis are maintained in the sintered ceramics. The same conclusion is drawn from spatially-resolved confocal Raman microscopy experiments on regions of a few microns. Field emission scanning electron microscopy has evidenced the substantial grain growth taking place during the sintering process - mean particle sizes rise from about 600 nm in the powders up to 3.8(6) um for dense LiFeO2 and 10(2) um for LiFe5O8 ceramics