Evolución del microrrelieve de la superficie del suelo medido a diferentes escalas

Se denomina microrrelieve de la superficie del suelo, o sencillamente rugosidad, a la configuración de la superficie, a su microtopografía, desde la escala milimétrica hasta la métrica. La rugosidad de la superficie influye considerablemente en el reparto de agua de lluvia entre infiltración y escorrentía. El almacenamiento temporal de agua en las pequeñas depresiones que se forman entre agregados y terrones es un parámetro importante para la modelización de procesos erosivos. En este trabajo se revisan las técnicas disponibles para caracterizar la microtopografía del suelo, poniendo particular énfasis en las diferencias entre métodos destructivos o de contacto y telemétricos, que también presentan distinta la resolución de medida y destacando la indudable ventaja de los segundos para analizar la evolución de la superficie del suelo. En un caso, se estudió el efecto del contenido hídrico inicial sobre la evolución de la microtopografía de un lecho de siembra bajo la acción de lluvia simulada, tras caracterización mediante rugosímetro laser. Para ello, se establecieron dos condiciones iniciales diferentes, suelo seco y húmedo, lo que permitió evaluar la importancia relativa de dos de los principales mecanismos de desagregación, estallido por aire ocluido e impacto de la gota de lluvia, sobre el desmoronamiento del microrrelieve de la superficie original. Se pudo comprobar la mayor velocidad de evolución de la superficie inicial seca, como consecuencia de la acción del aire atrapado. En otro caso se estudió el efecto del laboreo en la evolución de la rugosidad bajo la acción del agua de lluvia natural, en condiciones climáticas tropicales. Se partió de superficies creadas por arado y arado + niveladora. La caracterización del microrrelieve se efectuó mediante un rugosímetro de agujas y se pudo comprobar que la superficie inicial originada por laboreo primario evolucionaba más rápidamente. En los dos casos estudiados la evolución degradativa se expresó cuantitativamente tanto en términos de disminución de la rugosidad aleatoria como de reducción del agua de lluvia almacenada en las depresiones de la superficie / Soil surface microrelief, or singly roughness, is refered to as the the milimeter scale configuration or microtopography variations of the soil surface within a meter scale area. Roughness considerably influences rainfall repartition between infiltration and runoff. Soil surface temporal storage of water in the small depression formed by clods and individual aggregates is tought to be an important parameter for modelling erosive processes. Current available techniques for characterizing soil surface microtopography were reviewed in this paper, so that particular emphasis has been placed on the differences between contact or destructive methods and non-contact methods. Because both types of methods are also characterized by a different scale resolution, noncontact devices are considered most adequates for soil surface evolution studies. The first case study assessed the effect of initial soil water content on the microrelief evolution of an artificial seedbed. Measurements were made before and after simulated rainfall using a noncontact laser profile meter. Two different soil initial conditions were studied, moist and dry, which allowed to assess the relative importance of the most important desagregation mechanisms which are responsible for decay of the original soil surface microrelief, namely rupture induced by trapped air action and impact of rainfall drops. As expected, a faster evolution of the dry surface was observed, which was explained by occluded air effects. The second case study was devoted to tillage effects on soil roughness. Field experiences were made under natural rainfall in subtropical climate. Initial surfaces were created by mouldboard plow and mouldboard plow + .disked. Soil surface microrelief was characterized by means of a pinmeter. A faster evolution of the soil surface resulting from primary tillage was observed. In the two study cases microrelief decay could we quantitatively assessed both, using the random roughness and the surface water storage parametersGalicia. Consellería de Economía e Industria; PGIDT01 AGR10302 PRMinisterio de Ciencia y Tecnología; REN2000-04445-C02-01-H

Congreso Internacional en Comunicación Política y Estrategias de Campañas (1º.)

Producción CientíficaLas webs electorales de los partidos políticos españoles continuaron durante la campaña de 2011 en la línea mostrada de 2008 de acusada orientación al cibermarketing con pocos signos de ciberdemocracia, tal y como había detectado el análisis realizado sobre aquella campaña por Dader, Campos, Vizcaíno y Cheng (2011). Un análisis preliminar cualitativo de la es tructura y contenidos de las webs de las ocho formaciones principales que han obtenido representación parlamentaria en noviembre de 2011 corrobora la impresión de que nuestros partidos apenas explotan las posibilidades de diálogo ciudadano e información de tallada que son inherentes a la herramienta web aplicada a la política. En su lugar siguen incorporando nuevos recursos de impacto emocional y apelatividad propagandístico - publicitaria, reduciendo incluso las secciones de sus páginas dedicadas al debate con los electores o la participación de éstos en la generación de propuestas o de argumentación política. La aplicación de un Índice de Transparencia, diseñado específicamente para esta investigación mediante la elaboración de una Tabla de 49 items formales, permite además asegurar que el grado de transparencia de estos partidos políticos respecto a datos esenciales de su estructura organizativa, objetivos y actividad queda muy lejos de los ideales de accesibilidad y claridad informativa que propugna la propuesta democrática del GOBIERNO ABIERTO y las instituciones políticas abiertas a la ciudadanía

Gliding Box method applied to trace element distribution of a geochemical data set

The application of fractal theory to process geochemical prospecting data can provide useful information for evaluating mineralization potential. A geochemical survey was carried out in the west area of Coruña province (NW Spain). Major elements and trace elements were determined by standard analytical techniques. It is well known that there are specific elements or arrays of elements, which are associated with specific types of mineralization. Arsenic has been used to evaluate the metallogenetic importance of the studied zone. Moreover, as can be considered as a pathfinder of Au, as these two elements are genetically associated. The main objective of this study was to use multifractal analysis to characterize the distribution of three trace elements, namely Au, As, and Sb. Concerning the local geology, the study area comprises predominantly acid rocks, mainly alkaline and calcalkaline granites, gneiss and migmatites. The most significant structural feature of this zone is the presence of a mylonitic band, with an approximate NE-SW orientation. The data set used in this study comprises 323 samples collected, with standard geochemical criteria, preferentially in the B horizon of the soil. Occasionally where this horizon was not present, samples were collected from the C horizon. Samples were taken in a rectilinear grid. The sampling lines were perpendicular to the NE-SW tectonic structures. Frequency distributions of the studied elements departed from normal. Coefficients of variation ranked as follows: Sb < As < Au. Significant correlation coefficients between Au, Sb, and As were found, even if these were low. The so-called ‘gliding box’ algorithm (GB) proposed originally for lacunarity analysis has been extended to multifractal modelling and provides an alternative to the ‘box-counting’ method for implementing multifractal analysis. The partitioning method applied in GB algorithm constructs samples by gliding a box of certain size (a) over the grid map in all possible directions. An “up-scaling” partitioning process will begin with a minimum size or area box (amin) up to a certain size less than the total area A. An advantage of the GB method is the large sample size that usually leads to better statistical results on Dq values, particularly for negative values of q. Because this partitioning overlaps, the measure defined on these boxes is not statistically independent and the definition of the measure in the gliding boxes is different. In order to show the advantages of the GB method, spatial distributions of As, Sb, and Au in the studied area were analyzed. We discussed the usefulness of this method to achieve the numerical characterization of anomalies and its differentiation from the background from the available data of the geochemistry surve

Endocannabinoid System and Synaptic Plasticity: Implications for Emotional Responses

The endocannabinoid system has been involved in the regulation of anxiety, and proposed as an inhibitory modulator of neuronal, behavioral and adrenocortical responses to stressful stimuli. Brain regions such as the amygdala, hippocampus and cortex, which are directly involved in the regulation of emotional behavior, contain high densities of cannabinoid CB1 receptors. Mutant mice lacking CB1 receptors show anxiogenic and depressive-like behaviors as well as an altered hypothalamus pituitary adrenal axis activity, whereas enhancement of endocannabinoid signaling produces anxiolytic and antidepressant-like effects. Genetic and pharmacological approaches also support an involvement of endocannabinoids in extinction of aversive memories. Thus, the endocannabinoid system appears to play a pivotal role in the regulation of emotional states. Endocannabinoids have emerged as mediators of short- and long-term synaptic plasticity in diverse brain structures. Despite the fact that most of the studies on this field have been performed using in vitro models, endocannabinoid-mediated plasticity might be considered as a plausible candidate underlying some of the diverse physiological functions of the endogenous cannabinoid system, including developmental, affective and cognitive processes. In this paper, we will focus on the functional relevance of endocannabinoid-mediated plasticity within the framework of emotional responses. Alterations of the endocannabinoid system may constitute an important factor in the aetiology of certain neuropsychiatric disorders, and, in turn, enhancers of endocannabinoid signaling could represent a potential therapeutical tool in the treatment of both anxiety and depressive symptoms

Functional macroporous iron-phosphorous films by electrodeposition on colloidal crystal templates

Altres ajuts: Oréal-Unesco For Women in Science programme. The authors would like to acknowledge networking support by the COST Action e-MINDS MP1407Pseudo-ordered macroporous iron-phosphorous (Fe-P) films have been electrodeposited potentiostatically from a citrate-sulfate bath onto Au surfaces pre-patterned with a colloidal crystal mask of polystyrene spheres of 350 nm in diameter. The electrolyte contained sodium hypophosphite as the P source, enabling the incorporation of 6-14 at.% P. For comparative purposes, continuous films have been obtained galvanostatically on unpatterned Au surfaces. In both cases, the P content could be varied to a certain extent by adjusting the deposition potential or current density. Tunable microstructure and magnetic response was observed due to the dissimilar chemical composition, with coercivity values being larger in the macroporous films. Additionally, wettability analyses showed that these were more hydrophobic, reaching contact angle values of about 130∘. In spite of their hydrophobic character, the samples were catalytic toward oxygen evolution reaction (OER) in alkaline media. The macroporous Fe-P films showed faster kinetics for OER than their nonporous counterparts. Our results show that electrodeposited porous Fe-P based materials show an interesting combination of properties which make them appealing for applications including water cleaning, soft-magnetic components, or electrocatalytic production of oxygen, to name a fe

Water Erosion from Agricultural Land Under Atlantic Climate

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Defects on a pyrite(100) surface produce chemical evolution of glycine under inert conditions : experimental and theoretical approaches

Acknowledgements This work has been supported by the MINECO project ESP2017-89053. The Instituto Nacional de Tecnica Aeroespacial supported the work performed at CAB. EER is thankful to Javier Martin-Torres, Alfonso Hernandez-Laguna and C. M. Pradier for their support and suggestions. This Project has been partially funded by the Spanish State Research Agency (AEI) Project No. MDM-2017-0737 Unidad de Excelencia ‘‘Marıa de Maeztu’’-Centro de Astrobiologıa (CSIC-INTA).Peer reviewedPublisher PD

Evaluación del almacenamiento temporal de agua en depresiones del microrrelieve

Jornadas de Investigación en la Zona No Saturada de Suelo, ZNS 2005, A Coruña, 16-18 de noviembre de 2005La rugosidad de la superficie del suelo es un parámetro que puede afectar considerablemente a las propiedades hidrológicas del mismo. La estimación del almacenamiento temporal de agua en microdepresiones (ATM), esto es, el volumen de agua que puede ser almacenado en las hondonadas antes del inicio de la escorrentía, resulta útil para la profundización en el conocimiento y la modelación de los procesos erosivos. El objetivo de este trabajo es comparar diferentes métodos de cálculo del ATM, empleando modelos empíricos y geométricos, en superficies de suelo cubiertas con cantidades crecientes de residuos vegetales. Las estimaciones de ATM se efectuaron a partir de medidas de microrrelieve que se efectuaron mediante rugosímetro de agujas y rugosímetro laser en redes de 30mm x 30 mm y de 2 mm x 2 mm, respectivamente. La magnitud del volumen de ATM depende en gran medida de las condiciones de borde consideradas en la modelación y de las características de la red de muestreo. Debido al pequeño tamaño de las parcelas experimentales, parece realista usar modelos que tengan en cuenta el efecto de borde. Cuando se modifica la resolución de la red de muestreo, aumentando el tamaño de la celdilla, no se aprecian diferencias significativas en los valores de la rugosidad aleatoria, RR, ni tampoco del almacenamiento potencial en microdepresiones, ATM, estimado teniendo en cuenta el efecto de borde. Sin embargo, si se considera que existe drenaje libre en los bordes de la pequeña parcela experimental los valores de ATM tienden a disminuir conforme disminuye la resolución. En ambos casos, con y sin efecto de borde, se aprecia un aumento de la imprecisión de los datos de RR y ATM al aumentar la escala de medida. La topografía de la superficie del suelo presenta una gran dependencia espacial, que está relacionada con el tamaño de unidades estructurales como terrones y agregados, y el almacenamiento temporal se ve afectado, de modo considerable, por la escala de medida y el tamaño de la parcela experimental / Soil surface roughness is a parameter that may influence considerably the hydraulic properties at the soil surface. Evaluation of maximum water depression storage (MDS), i.e. the absolute volume of water that potentially can be stored at a rough surface before water runoff starts, will be useful to increase knowledge and to improve modelling of erosive processes. This work aims at comparing different MDS estimation methods, using both empirical and geometrical models in soil surfaces covered with different crop residue amounts. Point elevations were measured by means of a pin meter and a laser relief meter; using 30 mm x 30 mm and 2 mm x 2 mm grids, respectively. Surface water depression storage was found to depend mainly on the type of boundary conditions assigned to the test surfaces and on the grid parameters. Because of the small size of the experimental plots, it was concluded that models taken into account plot boundary effects result in more realistic estimations. When resolution of the experimental plot is modified by increasing grid size, only minor differences in roughness roughness, RR, and maximum depressional storage, MDS, assessed by taking into account boundary effects values are not, were observed. However, when modelling is performed under free drainage conditions at the boundary of the small experimental plots, MDS values were found to decrease with decreasing grid resolution. In both studied cases, i.e. with and without boundary effect, accuracy of RR and MDS values increases as the grid resolution increases. Soil surface topography is characterized by high spatial dependence, associated with the size of soil structural units, aggregates and clods and maximum depressional storage is controlled by the upper and lower cutoff length scales of the sampled plot, i. e., grid resolution and plot siz