[Bulas relativas a la fundación de la Universidad Complutense de Alcalá de Henares de los Papas Julio II, Alejandro VII y Alejandro VI]

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Assisted phytoextraction by rhamnolipids of Cu contaminated soils

La fitoextracción de elementos potencialemente tóxicos (EPTs) es una técnica de recuperación de suelos medioambientalmente atractiva debido a que no precisa de excavaciones y transporte del suelo. Además, el uso de plantas hace que visualmente afecte muy poco al paisaje. Sin embargo la baja biodisponibilidad de los EPTs, hace que su aplicación sea muy reducida en suelos reales contaminados. Este trabajo presenta los estudios preliminares de la adición de ramnolípidos a 2 suelos con distintas propiedades contaminados con Cu para aumentar la disponibilidad del metal, y así incrementar la efectividad de la fitoextracción. Esta técnica se denomina fitoextracción asistida por quelatos. Los ramnolípidos son compuestos naturales de baja toxicidad con características biosurfactantes. En este ensayo no se ha encontrado un efecto positivo de la aplicación de ramnolípidos a una dosis de 1 g kg-1 en la capacidad de acumulación de Cu de dos cultivos, cebada y mostaza parda, así como tampoco se ha observado efecto incrementando la disponibilidad de metales en suelo. Esto parece indicar que el efecto de los ramnolípidos en el aumento de la capacidad de extracción de Cu en suelo es insuficiente para ser aplicados como sustancias que favorezcan la eficacia de la fitorecuperación asistida de Cu en suelos contaminados.Phytoextraction of Potentially Toxic Elements (PTEs) is a friendly soil restoration technique. It is environmentally attractive because excavation and soil transportation are not needed. Furthermore, plant use usually have a positive impact on the landscape. Nevertheless, low bioavailability of most PTEs, reduce drastically its real application in soil contamination. This research shows preliminary results of the addition of rhamnolipids to two Cu contaminated soils to increase metal availability, in order to get better results in soil phytoextraction. This technique is known as chelate assisted phytoextraction. Rhamnolipids are natural compounds showing low toxicity and biosurfactant characteristics. In this research a positive effect of rhamnolipids application (1 g kg-1 soil) on soil Cu extraction by two different crops (barley and Indian mustard) have not been observed. Similarly, increases in Cu soil bioavailability neither have been observed. It seems to indicate that the effect of rhamnolipids on the increases of Cu extractable content are not enough for using them as chelating agents to improve soil phytoextraction of Cu contaminated soils

Effect of soil type on adsorption-desorption processes of the fungicide Thiabendazole

Se han realizado ensayos de adsorción-desorción del fungicida Tiabendazol (TBZ) en once suelos con propiedades fisicoquímicas diferentes con el objetivo de estudiar su comportamiento en el sistema suelo-agua. Las isotermas de adsorción de TBZ se ajustaron a la ecuación de Freundlich, variando el valor de Kf entre 1.41 y 107. En gran parte de los suelos estudiados las Kf se relacionaron de forma directa con el contenido en materia orgá- nica, obteniéndose un valor medio de la constante Kfoc de 1650, por lo que ésta juega un papel importante en la adsorción. Sin embargo, teniendo en cuenta todos los suelos estudiados, Kfoc varió dentro de un amplio rango (210-5474), lo que indica que en ciertos suelos hay otras propiedades que también influyen en la adsorción, tales como el pH de los mismos y la presencia de óxidos amorfos. La desorción de TBZ presentó histéresis positiva en la mayoría de los suelos, indicando la parcial irreversibilidad de la adsorción. La adsorción se mostró más irreversible cuanto menor fué la cantidad adsorbida.In order to study the behavior of the fungicide Thiabendazole (TBZ) in the soil-water system, adsorptiondesorption tests were performed in eleven soils with different physicochemical properties. TBZ adsorption isotherms were well fitted to the Freundlich equation, and Kf values varied in the range 1.41-107. Kf was directly related to organic matter content in a great part of the soils, with an average Kfoc value of 1650, playing an important role in TBZ adsorption. However, taking into account all the studied soils, Kfoc varied in a wide range (210- 5474), indicating that in some soils other properties may influence on adsorption, such as their pH and the presence of amorphous oxides. Positive hysteresis was observed in TBZ desorption in most of the soils, indicating a partially irreversible adsorption. It was showed more irreversible as lower the adsorbed ammount

Study of Interactions Between Microbes and Minerals by Scanning Transmission X-Ray Microscopy (STXM)

Scanning Transmission X-ray Microscopy (STXM) and Transmission Electron Microscopy (TEM) were combined to characterize various samples of geomicrobiological interest down to the nanometer scale. An approach based on energy-filtered imaging was used to examine microbe-mineral interactions and the resulting biominerals, as well as biosignatures in simplified laboratory samples. This approach was then applied to natural samples, including natural biofilms entombed in calcium carbonate precipitates and bioweathered silicates and facilitated location of bacterial cells and provided unique insights about their biogeochemical interactions with minerals at the 30-40 nm scale

Chrysolcolla Redefined as Spertiniite

XAFS and {mu}-XAFS spectra were collected at the Cu K-edge for seven chrysocolla samples (Peru, USA, and Congo). The results suggest that the local structure around Cu is similar to that in Cu(OH){sub 2} (spertiniite). Cu-L{sub 3} STXM imaging and spectroscopy confirm that the chrysocolla samples examined here consist of mesoscopic Cu(II)-rich domains surrounded by Si-rich domains (in agreement with results from infra-red spectroscopy). Hence, we suggest that chrysocolla, which is generally considered to be orthorhombic with composition (Cu,Al){sub 2}H{sub 2}Si{sub 2}O{sub 5}(OH){sub 4} {center_dot} nH{sub 2}O, is in actually a mesoscopic assemblage composed dominantly of spertiniite (Cu(OH){sub 2}), water and amorphous silica (SiO{sub 2})

Lady Gaga as (dis)simulacrum of monstrosity

Lady Gaga’s celebrity DNA revolves around the notion of monstrosity, an extensively researched concept in postmodern cultural studies. The analysis that is offered in this paper is largely informed by Deleuze and Guattari’s notion of monstrosity, as well as by their approach to the study of sign-systems that was deployed in A Thousand Plateaus. By drawing on biographical and archival visual data, with a focus on the relatively underexplored live show, an elucidation is afforded of what is really monstrous about Lady Gaga. The main argument put forward is that monstrosity as sign seeks to appropriate the horizon of unlimited semiosis as radical alterity and openness to signifying possibilities. In this context it is held that Gaga effectively delimits her unique semioscape; however, any claims to monstrosity are undercut by the inherent limits of a representationalist approach in sufficiently engulfing this concept. Gaga is monstrous for her community insofar as she demands of her fans to project their semiosic horizon onto her as a simulacrum of infinite semiosis. However, this simulacrum may only be evinced in a feigned manner as a (dis)simulacrum. The analysis of imagery from seminal live shows during 2011–2012 shows that Gaga’s presumed monstrosity is more akin to hyperdifferentiation as simultaneous employment of heterogeneous and potentially dissonant inter pares cultural representations. The article concludes with a problematisation of audience effects in the light of Gaga’s adoption of a schematic and post-representationalist strategy in the event of her strategy’s emulation by competitive artists

On the influence of the cosmological constant on gravitational lensing in small systems

The cosmological constant Lambda affects gravitational lensing phenomena. The contribution of Lambda to the observable angular positions of multiple images and to their amplification and time delay is here computed through a study in the weak deflection limit of the equations of motion in the Schwarzschild-de Sitter metric. Due to Lambda the unresolved images are slightly demagnified, the radius of the Einstein ring decreases and the time delay increases. The effect is however negligible for near lenses. In the case of null cosmological constant, we provide some updated results on lensing by a Schwarzschild black hole.Comment: 8 pages, 1 figure; v2: extended discussion on the lens equation, references added, results unchanged, in press on PR

Planck 2013 results. XXII. Constraints on inflation

We analyse the implications of the Planck data for cosmic inflation. The Planck nominal mission temperature anisotropy measurements, combined with the WMAP large-angle polarization, constrain the scalar spectral index to be ns = 0:9603 _ 0:0073, ruling out exact scale invariance at over 5_: Planck establishes an upper bound on the tensor-to-scalar ratio of r < 0:11 (95% CL). The Planck data thus shrink the space of allowed standard inflationary models, preferring potentials with V00 < 0. Exponential potential models, the simplest hybrid inflationary models, and monomial potential models of degree n _ 2 do not provide a good fit to the data. Planck does not find statistically significant running of the scalar spectral index, obtaining dns=dln k = 0:0134 _ 0:0090. We verify these conclusions through a numerical analysis, which makes no slowroll approximation, and carry out a Bayesian parameter estimation and model-selection analysis for a number of inflationary models including monomial, natural, and hilltop potentials. For each model, we present the Planck constraints on the parameters of the potential and explore several possibilities for the post-inflationary entropy generation epoch, thus obtaining nontrivial data-driven constraints. We also present a direct reconstruction of the observable range of the inflaton potential. Unless a quartic term is allowed in the potential, we find results consistent with second-order slow-roll predictions. We also investigate whether the primordial power spectrum contains any features. We find that models with a parameterized oscillatory feature improve the fit by __2 e_ _ 10; however, Bayesian evidence does not prefer these models. We constrain several single-field inflation models with generalized Lagrangians by combining power spectrum data with Planck bounds on fNL. Planck constrains with unprecedented accuracy the amplitude and possible correlation (with the adiabatic mode) of non-decaying isocurvature fluctuations. The fractional primordial contributions of cold dark matter (CDM) isocurvature modes of the types expected in the curvaton and axion scenarios have upper bounds of 0.25% and 3.9% (95% CL), respectively. In models with arbitrarily correlated CDM or neutrino isocurvature modes, an anticorrelated isocurvature component can improve the _2 e_ by approximately 4 as a result of slightly lowering the theoretical prediction for the ` <_ 40 multipoles relative to the higher multipoles. Nonetheless, the data are consistent with adiabatic initial conditions