A comparative Digital Soil Mapping (DSM) study using a non-supervised clustering analysis and an expert knowledge based model - A case study from Ahuachapán, El Salvador

DSM is the inference of spatial and temporal soil property variations using mathematical models based on quantitative relationships between environmental information and soil measurements. The quality of DSM information depends on the method and environmental covariates used for its estimations. We compared two DSM methods to predict soil properties such as Organic Matter “MO” (%), Sand (%), Clay (%), pH (H2O), Phosphorus (mg/kg), Effective Cationic Exchange Capacity “CICE” (cmol/L), Potassium (cmol/L) and Water Holding Capacity (mm/m) for the department of Ahuachapán in El Salvador to support the activities of the Agriculture Landscape Restoration Initiative (ALRI) in the countr

A comparative Digital Soil Mapping (DSM) study using a non-supervised clustering analysis and an expert knowledge based model - A case study from Ahuachapán, El Salvador

DSM is the inference of spatial and temporal soil property variations using mathematical models based on quantitative relationships between environmental information and soil measurements. The quality of DSM information depends on the method and environmental covariates used for its estimations. We compared two DSM methods to predict soil properties such as Organic Matter “MO” (%), Sand (%), Clay (%), pH (H2O), Phosphorus (mg/kg), Effective Cationic Exchange Capacity “CICE” (cmol/L), Potassium (cmol/L) and Water Holding Capacity (mm/m) for the department of Ahuachapán in El Salvador to support the activities of the Agriculture Landscape Restoration Initiative (ALRI) in the countr

Programación fetal, estrés toxico intrauterino y consecuencias en el producto: Fetal programmig, intrauterine toxic stress and consequences on the product

Dos décadas atrás Baker dio el concepto de Programación Fetal (PF), donde asociaba el ambiente prenatal y el desarrollo del feto. En consecuencia, la PF representaría “la inducción de las respuestas fetales debido al entorno uterino” que condicionará cambios funcionales y estructurales en el propio feto, con repercusión a corto y largo plazo. En consecuencia, si el ambiente prenatal es adverso en el desarrollo, tendremos posiblemente patologías en la vida extra uterina. Las evidencias señalan, que procesos implicados en el desarrollo de diversas funciones de los sistemas orgánicos complejos, se iniciarían mucho antes del nacimiento y conformarían problemáticas de salud a futuro

Characterization of quaternary ammonium compounds in Flourensia xerophytic communities and response to UV-B radiation

As part of ongoing studies aimed at characterizing molecular components involved in the ecophysiological adaptations of native xerophytic plants from central Argentina, we demonstrated the presence of compatible solutes in Flourensia campestris (FC) and Flourensia oolepis (FO), specifically glycine betaine (GB) through TLC, LC, 1H NMR and 13C-NMR. GB content (leaves: 38±7μmolg-1 DW; adult plants>seedlings), and distribution (capitula>vegetative leaves>reproductive leaves>shoots>roots) were similar to other quaternary ammonium compound (QAC) accumulators. Flourensia seedlings from both species protected from UV-B exposure - a major abiotic stress in these natural environments - showed a significant increase of GB in the leaves (p<0.01) and a significant decrease in the roots (p<0.05). In FC and FO xerophytic shrub-dominated communities QACs were detected for the first time in 41% of co-occurring species (N=39), 14 of 28 natives (50%) and 2 of 11 exotics (18%), being GB in natives only (57% of QAC accumulators). GB may be considered as a chemotaxonomical character for the genus Flourensia, since it was also detected in Flourensia hirta, Flourensia niederleinii, Flourensia riparia, Flourensia fiebrigii, Flourensia macroligulata and Flourensia heterolepis. Our controlled UV-B experiments, set up in the same natural environment where these species grow, clearly show that solar UV-B - and therefore oxidative stress - is involved in regulating GB contents and within-plant distribution in FC and FO seedlings. The findings in Flourensia co-occurring native species suggest that QACs accumulation may be considered as a community-specific ecophysiological trait in these xerophytic environments. .Fil: Piazza, Leonardo A.. Universidad de Buenos Aires. Facultad de Agronomia. Sede Polo Universitario Punilla Centro; ArgentinaFil: López, D.. Universidad de Buenos Aires. Facultad de Agronomia. Sede Polo Universitario Punilla Centro; ArgentinaFil: Silva, Mariana Paola. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Agronomia. Sede Polo Universitario Punilla Centro; ArgentinaFil: Lopez Rivilli, Marisa Juana. Universidad de Buenos Aires. Facultad de Agronomia. Sede Polo Universitario Punilla Centro; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Cantero, Juan Jose. Universidad Nacional de Río Cuarto. Facultad de Agronomía y Veterinaria; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Tourn, G. M.. Universidad de Buenos Aires. Facultad de Agronomia. Sede Polo Universitario Punilla Centro; ArgentinaFil: Scopel, Ana Leonor. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales; Argentin

Chemically tagging the Hyades Supercluster: A homogeneous sample of F6-K4 kinematically selected northern stars

Stellar kinematic groups are kinematical coherent groups of stars that might have a common origin. These groups are dispersed throughout the Galaxy over time by the tidal effects of both Galactic rotation and disc heating, although their chemical content remains unchanged. The aim of chemical tagging is to establish that the abundances of every element in the analysis are homogeneus among the members. We study the case of the Hyades Supercluster to compile a reliable list of members (FGK stars) based on our chemical tagging analysis. For a total of 61 stars from the Hyades Supercluster, stellar atmospheric parameters (Teff, logg, xi, and [Fe/H]) are determined using our code called StePar, which is based on the sensitivity to the stellar atmospheric parameters of the iron EWs measured in the spectra. We derive the chemical abundances of 20 elements and find that their [X/Fe] ratios are consistent with Galactic abundance trends reported in previous studies. The chemical tagging method is applied with a carefully developed differential abundance analysis of each candidate member of the Hyades Supercluster, using a well-known member of the Hyades cluster as a reference (vB 153). We find that only 28 stars (26 dwarfs and 2 giants) are members, i.e. that 46% of our candidates are members based on the differential abundance analysis. This result confirms that the Hyades Supercluster cannot originate solely from the Hyades cluster.Comment: A&A, in pres

Approximating Soil Organic Carbon Stock in the Eastern Plains of Colombia

In Colombia, the rise of agricultural and pastureland expansion continues to exert increasing pressure on the structure and ecological processes of savannahs in the Eastern Plains. However, the effect of land use change on soil properties is often unknown due to poor access to remote areas. Effective management and conservation of soils requires the development spatial approaches that measure and predict dynamic soil properties such as soil organic carbon (SOC). This study estimates the SOC stock in the Eastern Plains of Colombia, with validation and uncertainty analyses, using legacy data of 653 soil samples. A random forest model of nine environmental covariate layers was used to develop predictions of SOC content. Model validation was determined using the Taylor series method, and root-mean-squared error (RMSE) and mean error (ME) were calculated to assess model performance. We found that the model explained 50.28% of the variation within digital SOC content map. Raster layers of SOC content, bulk density, and coarse rock fragment within the Eastern Plains were used to calculate SOC stock within the region. With uncertainty, SOC stock in the topsoil of the Eastern Plains was 1.2 G t ha−1. We found that SOC content contributed nearly all the uncertainty in the SOC stock predictions, although better determinations of SOC stock can be obtained with the use of a more geomorphological diverse dataset. The digital soil maps developed in this study provide predictions of extant SOC content and stock in the topsoil of the Eastern Plains, important soil information that may provide insight into the development of research, regulatory, and legislative initiatives to conserve and manage this evolving ecosystem

First-best, second-best and principal-agent problems

In some pure moral hazard situations the principal can implement a first-best allocation using an incentive contract constructed on the basis of a first-best payment scheme. Such a contract relies on the possibility of discriminate actions according to the outcome by imposing a penalty whenever the observed outcome is lower than the admissible ones. The elimination of inefficient behavior depends basically on the outcome function, and we find that the fine is finite in the more interesting cases. The implementation of the first-best solution does not depend on the principal's risk neutrality. Nevertheless, when the principal is risk neutral, the ef f icient contract is dichotomous. Moreover, we prove that the efficient allocation can be reached through such a dichotomous payment scheme if and only if the principal is risk neutral for a certain range of returns.

Evaluación Hidrológica Superficial del Departamento de Ahuachapán, El Salvador: Iniciativa Raíces-Ahuachapán

Catholic Relief Services (CRS) está liderando la iniciativa “Raíces-Ahuachapán” (referida como Agricultural Landscape Restoration Initiative – ALRI en inglés), una iniciativa para promover agricultura restaurativa en paisajes críticos del departamento de Ahuachapán. Esta iniciativa está siendo financiada por la Fundación Howard G. Buffet y en estos momentos se encuentra en la fase 1/4 del plan estratégico propuesto hasta el 2030. CRS está implementando esta iniciativa en conjunto con tres instituciones del ámbito nacional (PRISMA, AZURE y CARITAS) y con el apoyo del Centro Internacional de Agricultura Tropical – CIAT, además de contar con el soporte de diferentes socios locales. La restauración de paisaje que se piensa realizar a través de esta iniciativa tiene como objetivo asistir a la recuperación de ecosistemas degradados, dañados o destruidos. Además, de implementar mejoras en tierras que han sido degradadas a una escala que permita la reconstrucción de la integridad ecológica y el mejoramiento de la vida de las personas. Dentro de los componentes de la iniciativa se quiere llevar a cabo la restauración de los servicios agroecosistémicos con un enfoque en la protección de los recursos hídricos en importantes áreas agrícolas. Basado en lo anterior, CIAT ha sido encargado de realizar una evaluación hidrológica del departamento de Ahuachapán que permita la identificación de áreas claves en la contribución de agua superficial tanto en época seca como de lluvia, a través de la combinación de herramientas de modelación hidrológica y sistemas de información geográfica (SIG)

Vortices in U(1) Noncommutative Gauge Fields

Charged vortex solutions for noncommutative Maxwell-Higgs model in 3+1 dimensions are found. We show that the stability of these vortex solutions is spoiled out for some, large enough, noncommutativity parameter. A non topological charge, however, is induced by noncommutative effects.Comment: references added, slight modifications in the introduction and conclusions. To be published in PR