Regularity of viscosity solutions to fully nonlinear elliptic transmission problems

We develop the regularity theory of viscosity solutions to transmission problems for fully nonlinear second order uniformly elliptic equations. Our results give a complete theory of existence, uniqueness, comparison principle, and regularity of solutions to flat interface transmission problems; and the $C^{0,\alpha}$, $C^{1,\alpha}$ and $C^{2,\alpha}$ regularity of viscosity solutions up to the transmission surface for the case of curved interfaces.Comment: Improved presentation. 37 page

Factores de enriquecimiento metálico en sedimentos holocenos del estuario del río Tinto (SO de España)

Metal concentration in sediments samples from two vibracores in the Tinto river estuary it has been determined. The enrichment factors (EF) of metal associated to sulphide deposits (Fe, Cu, Zn, Pb and As), in most cases, is over 2. Cu, Zn and As have much higher EF, over 10 in surficial samples. The progressive shallowness of the estuary has undergone a relative increase in acidic river water volume with respect to seawater. This effect has originated a downstream displacement of acid mixing processes affecting the estuary, which is reflected in higher metal concentration in sediments of the outer zones of the system

Biodisponibilidad de Fe y metales pesados en los sedimentos de la Ría de Huelva (SO de España)

Bioavailability of Fe, Cu, Zn, As, Cd and Pb has been studied in 17 samples of surface sediments of the Ria of Huelva. In all cases, total concentration of these elements is high, especially of Zn (1660,6 ppm), followed by Cu (1499,9 ppm), Pb (919,2 ppm), As (432,5 ppm) and Cd (2,7 ppm). The highest concentrations associated with bioavailable fractions are shown by Zn (86% of total concentration) followed by Cd (76,5%), Fe (59%), Cu (45%), As (32%) and Pb (31%). The main source of metal input are the Tinto and Odiel rivers, which acidic water (pH < 4) discharge coming from acid mine drainage (AMD) to the estuary. Acidic water inputs and mixing processes with sea water are the main control in the spatial distribution of metals and their association with the different target fractions

Estudio de los procesos de control geoquímico en sedimentos estuarinos mediante análisis factorial (estuario del río Tinto, SO de España)

It has been determined absolute concentrations of major and trace elements and granulometrics composition of two vibracores in the Tinto river estuary. Fe oxy-hydroxide precipitation and its scavenging effect on metals is the main control process on the chemical composition of sediment. Factorial analysis of principal components allows recognizing four groups, the first one is composed by metals associated to Fe2O3 and P2O5 (Cr, Cu, Zn, Pb, Ni, As, Cd, U, Mn, Co and Se). The second one related Ba, Rb, Y, Zr, Th and Sc with K2O and mud. The third group indicates the presence of phyllosilicates and heavy minerals, and is made up of Cr, Ni, Zr, Li, Be, Y and V. The last one, formed by CaO and Sr, represents the carbonate presence of biogenic origin

Anomalías en REE como indicador de contaminación por vertidos de fosfoyesos en el estuario de los ríos Tinto y Odiel (SO de España)

In two cores in the Odiel and Tinto river estuary, Sc, Y, Th and Cu concentrations show a significant increase in the intermediate levels, between 10 and 40 cm depth. Vertical evolution patterns for Sc, Y, Cu and heavy rare earth (HREE) are similar, and contrary to those shown by Th, light REE (LREE) and middle REE (MREE). Samples of the intermediate levels of the cores show significant enrichment of REE relative to North American Shale Composite (NASC) and high values in the (La/Gd)NASC and (La/Yb)NASC ratios. These anomalies in the fractionation patterns caused by enrichments in LREE and MREE concentrations are related to the presence of high concentrations of Th. They were generated by effluents from fertilizer factories between 1968 and 1998 which used phosphorite as source material

Fraccionamiento de Fe y metales pesados en la Materia en Suspensión de la Ría de Huelva (SO de España)

It has studied the fractionation of Fe and several metals in 24 suspended matter samples collected during two cruises in the Ria de Huelva surface water. In all cases are observed high concentrations of Fe (7,4%) and metals. Among metals the most elevated average concentrations correspond to Cu (2834 ppm) followed by Zn (1921 ppm), Pb (344 ppm), As (139 ppm), Cd (22 ppm) and Ni (19 ppm). These high concentrations match with the high amounts of these same elements in surface sediments of this estuarine system and are originated by the acid contributions of the Tinto and Odiel rivers. They are observed throughout the system, from the mixing zones of both rivers to the interchange channels with the near coast. The fractionation analysis indicates that an important part of the total concentration of the studied elements is associated to phases with high chemical mobility, thus, more of 50% of the As, Cd and Pb concentrations present in the suspended matter correspond to labiles or very labiles fractions

Estudio de las concentraciones de REE y patrones de fraccionamiento en sedimentos superficiales del estuario de los ríos Tinto y Odiel (SO de España)

Sc, Y, Th, Cu and rare earth elements (REE) concentrations have been analyzed in 14 samples of surface sediments by means of ICP-MS. Mean concentrations of Sc, Y and Th in these sediments are lower than those presents in the Upper Continental Crust (UCC). Cu concentration is very high and is caused by inputs from the Odiel and Tinto rivers, affected by acid mine drainage. åREE mean concentration is lower than that observed in other rivers and estuaries. Plots of North American Shale Composite (NASC)-normalized REE data of surface sediments show a slight depletion in REE concentrations. Most samples present with middle REE enrichment relative to light REE and heavy REE