Short-term microbial response after laboratory heating and ground mulching adition.

Fire alters soil organic matter inducing quantitative and qualitative changes that presumably will affect post-fire soil microbial recolonisation. Several studies have evidenced marked soil organic carbon reduction after moderate and high intensity fire, which limit the total recovery of microbial biomass during years. In order to evaluate the role of soil organic matter alteration in short-term microbial colonization process, we perform a preliminary experiment where unaltered soil from Sierra Nevada Natural Park was heated at 300 ºC during 20 minutes in a muffle furnace (H300) to simulate a medium-high intensity fire. After heating, soil samples were inoculated with unaltered fresh soil, rewetted at 55-65% of water holding capacity and incubated during 3 weeks. At the same time, unheated soil samples were incubated under the same conditions as control (UH). In addition, trying to partially alleviate soil organic matter fire-induced alterations effects on microbial colonization, we include an organic amendment treatment (M+). So, part of heated and unheated samples were amended with a mix of ground alfalfa:straw (1:1) and soil microbial abundance and activity were monitored together with soil organic matter changes. Heating process reduces total organic carbon content. After one week of incubation carbon content in heated samples was lower than the control one, in both, amended and un-amended samples. Microbial biomass and respiration were negatively affected by heating. Ground mulching addition increase microbial biomass and respiration but was not enough to reach control values during the whole study. Nevertheless, viable and cultivable fungi and bacteria showed different pattern. After two weeks of incubation both, fungi and bacteria were higher in heated samples. Ground mulching addition appears to stimulate fungal response in both, heated and unheated samples. Preliminary results of this experiment evidence the transcendence of soil organic matter fire-induced changes on microbial colonization process and the importance to determine several microbial parameters to obtain a more faithful conclusion about microbial response. The organic amendment appears to alleviate partially heated-induced damage, highlighting the positive stimulation on fungal abundance in both, heated and unheated samples.This research has been funded by the Spanish Ministry of Economy and Competitiveness, through research projects POSTFIRE (CGL2013-47862-C2-1-R) and GEOFIRE (CGL2012-38655-C04-01)Peer Reviewe

Nuclear effects in neutrino and antineutrino CCQE scattering at MINERvA kinematics

We compare the charged-current quasielastic neutrino and antineutrino observables obtained in two different nuclear models, the phenomenological SuperScaling Approximation and the Relativistic Mean Field approach, with the recent data published by the MINERvA Collaboration. Both models provide a good description of the data without the need of an ad hoc increase in the mass parameter in the axial-vector dipole form factor. Comparisons are also made with the MiniBooNE results where different conclusions are reached.Comment: 6 pages, 7 figures, Accepted for publication in Physical Review

Fire impact and assessment of post-fire actions of a typical Mediterranean forest from SW Spain

Poster presentado en lal EGU General Assembly 2015, held 12-17 April, 2015 in Vienna, Austria. id.2248Wildfires may cause significant changes in soil physical and chemical properties. In addition, soil organic matter (SOM) content and chemical properties are usually affected by fire. Fire impacts may negatively affect soil health and quality, and induce or enhance runoff generation and, thereby, soil erosion risk and cause damages to the habitat of species. This fact is especially dramatic in Mediterranean ecosystems, where forest fires are a frequent phenomenon and restoration strategies are a key issue. The goals of this study are to determine: i) the immediate effects of fire on soil properties, including changes occurred in the quantity and quality of SOM and ii) the effect of post-fire actions on soil properties. In August 2012, a wildfire affected a forest area of approx. 90 ha in Montellano (Seville, SW Spain; longitude 37.00 º, latitude -5.56 º). This area is dominated by pines (Pinus pinaster and Pinus halepensis), and eucalypts (Eucaliptus globulus) with a Mediterranean climate. Dominant soil types are Rendzic Leptosols and Calcaric Haplic Regosols. It is a poorly limestone-developed soil (usually swallower than 25 cm). Four soil subsamples were collected 1 month and 25 months after fire within an area of approximately 200 m2. Subsamples were mixed together, homogenized, air-dried, crushed and sieved (2 mm). One control sample was collected in an adjacent area. The litter layer was removed by hand and studied separately. Branches, stems, bushes and plant residues on the fire-affected area were removed 16 months after the fire using heavy machinery as part of the post-fire management. The present research focuses on the study of the elemental composition (C, H and N) and physical properties (pH, water holding capacity, electrical conductivity) of bulk soil samples, and on the spectroscopic analysis (FT-IR, 13C NMR) and analytical pyrolysis data obtained from bulk the oils and from the humic acid fraction. immediate effects of fire, including the charring of vegetation and litter, as the input of charred residues may contribute to increase the total amount of soil organic matter. The post-fire removal of vegetation probably contributed to an additional loss of soil material due to an increase of the erosion risk. In addition, preliminary results point out that the burnt soil is not being recovered to the pre-fire conditions at a molecular level neither in the elemental composition. Results of this study will constitute a valuable tool for stake holders and decision makers to avoid additional alterations caused by post fire management of fire affected forests.Peer Reviewe

Non-volatility of ferroelectric SBT thin fims, at 75ºC

[ES] El estudio de la no volatilidad de una memoria FeRAM de tantalato de bismuto y estroncio, SrBi2Ta2O9 (SBT) en condiciones reales de uso, requiere la caracterización ferroeléctrica del material en forma de lámina delgada a temperaturas por encima del ambiente. Para ello se han depositado láminas de SBT mediante un método sol-gel, sobre substratos de Pt/TiO2/SiO2/Si(100), seleccionándose condensadores de área 5.10-4 cm-2. Basándonos en las medidas de la variación de la polarización con el tiempo (retención) realizadas a temperatura ambiente y a 75ºC, analizamos la viabilidad del material como una FeRAM en condiciones reales de uso.[EN] The study of the non-volatility of Strontium bismuth tantalate SrBi2Ta2O9 (SBT) FeRAM memory, at real operating conditions, requires the ferroelectric characterisation of the material, as a thin film, above the room temperature.As a result, it has been deposited SBT films by the sol-gel method, onto Pt/TiO2/SiO2/Si (100) substrates, using capacitors of 5 x 10–4 cm-2 .In this work, we analysed the viability of this material as a FeRAM memory in real operating conditions, as a result of the variation of the polarisation measurements with time (retention), performed at room temperature and 75ºC.Este trabajo ha sido realizado con el apoyo del proyecto de la CICYT MAT98-1068.Peer reviewe

Steel passive state stability in activated fly ash mortars

[EN] The present study explores the behaviour of structural steel embedded in Portland cement (OPC) mortars and NaOH- and NaOH+waterglass-activated fly ash, in the presence and absence of 2% Cl- (CaCl2). Variations were determined in the corrosion potential (Ecorr), linear polarization resistance (Rp) and corrosion current density (icorr) under different environmental conditions (90 days at 95% relative humidity (RH), 30 days at ≈30 % RH, 760 days at ≈ 95% RH). In the absence of Cl-, fly ash mortars were able to passivate steel reinforcement, although the stability of the passive state in changing environmental conditions was found to depend heavily on the activating solution used. Steel corrosion in the presence of 2% Cl- was observed to be similar to the corrosion reported for the material in OPC mortars.[ES] En el presente trabajo se estudia el comportamiento del acero estructural embebido en morteros de cemento Pórtland (OPC) y de cenizas volantes activadas con NaOH y una mezcla de NaOH y waterglass, en ausencia y en presencia de un 2% de Cl- (CaCl2). Se determinó la evolución del potencial de corrosión (Ecorr), la resistencia de polarización lineal (Rp) y la intensidad de corrosión (icorr), variando las condiciones ambientales (90 días al 95% de humedad relativa(HR) -30 días a ≈ 30% HR- 760 días a ≈ 95% HR).En ausencia de Cl- los morteros de cenizas volantes activadas pueden pasivar los refuerzos de acero, si bien la estabilidad del estado pasivo ante cambios en las condiciones ambientales parece mostrar una fuerte dependencia de la solución activadora empleada. Enpresencia de un 2% de Cl- los aceros se corroen mostrando en comportamiento similar al observado en morteros en base OPC.Peer reviewe

Razón de sexos y morfometría de Calidris minutilla (Aves, Scolopacidae) en Cuba: un análisis a partir de especímenes en colecciones científicas

Las poblaciones de Calidris minutilla (zarapiquito) presentan variaciones morfométricas tanto en los lugares de cría como en los de invernada. Se documentan la razón de sexos (N = 99) y medidas morfométricas (N = 49) del zarapiquito en Cuba a partir de especímenes conservados en colecciones científicas. Además, se evalúan posibles variaciones en la longitud del pico teniendo en cuenta la ubicación longitudinal (grados) y el tipo de zona costera donde fue realizado el muestreo. La proporción de hembras fue del 0,47 y las medidas morfométricas estaban dentro del rango descrito para esta especie. Las variaciones en la longitud del pico fueron atribuibles únicamente al sexo y no a las características del lugar de captura.Calidris minutilla (Least Sandpiper) populations exhibit morphometric variation across breeding and wintering sites. We documented sex ratio (N = 99) and morphological measurements (N = 49) of Least Sandpiper inhabiting Cuba using specimens in museum collections. We also assessed bill length variation in relation to the longitude (degrees) and type of coastal zone where sampling was conducted. Proportion of female was 0.47 and morphometric measurements were within the range described for the species. Differences in bill length were explained by sex but not by sampling site characteristics.Las poblaciones de Calidris minutilla (zarapiquito) presentan variaciones morfométricas tanto en los lugares de cría como en los de invernada. Se documentan la razón de sexos (N = 99) y medidas morfométricas (N = 49) del zarapiquito en Cuba a partir de especímenes conservados en colecciones científicas. Además, se evalúan posibles variaciones en la longitud del pico teniendo en cuenta la ubicación longitudinal (grados) y el tipo de zona costera donde fue realizado el muestreo. La proporción de hembras fue del 0,47 y las medidas morfométricas estaban dentro del rango descrito para esta especie. Las variaciones en la longitud del pico fueron atribuibles únicamente al sexo y no a las características del lugar de captura

Electrical activity of crystal defects in multicrystalline Si

Producción CientíficaUpgraded metallurgical-grade silicon solar cells with different ranges of efficiencies have been characterized by light-beam-induced current (LBIC) measurements. The interaction between grain boundaries and metallic impurities is studied for cells fabricated on wafers from different solidification heights of the ingot. A tight relation is observed between the electrical activity of the grain boundaries and the position of the wafer in the ingot, which is related to the impurity contamination. The presence of a large amount of metallic impurities enhances the electrical activity of the grain boundaries. The main features of the LBIC images are discussed in relation to the presence of metallic impurities.Junta de Castilla y León (project VA283P18)Ministerio de Economía, Industria y Competitividad (project ENE2017-89561-C4-3-R

Weak localization and electron-electron interaction in the layered compound CuFeTe2

The study of the electrical properties of the layered compound CuFeTe2 shows that there are three well differentiated conduction regimes depending on the temperature. Below TSDW ~ 300 K the formation of a Spin Density Wave (SDW) state has been reported, in the frame of a metal to non metal transition. Below 100 K (~ TSDW/3) the behavior of the electrical resistance as a function of temperature and magnetic field is attributable to the still present not condensed electrons (quasi particles) in the SDW state. At low temperatures (1.8 - 20K), low current (< 1 mA) and magnetic eld (0<H <6 Tesla), the effects of weak localization and electronic interactions in two dimensions appear. At intermediate temperatures (20 < T < 100 K) a hopping conductivity behavior is observed