Intensidad tecnológica de las exportaciones de El Salvador

La sofisticación de la producción de bienes y servicios de un país puede tener impactos positivos en el crecimiento y desarrollo económicos de dicho país. Por otro lado, la identificación de la ventaja comparativa en las exportaciones de bienes y servicios permitiría determinar qué productos y/o servicios debería especializar o diversificar sus exportaciones. A partir de datos del Sistema de Estadísticas de Comercio (SEC) de la Secretaria de Integración Centroamericana (SIECA) y de una clasificación de la intensidad de tecnológica de las exportaciones desarrollada por la Comisión Económica para América Latina (CEPAL) se analizará la ventaja comparativa de los productos de exportación con algún nivel de intensidad tecnológica de El Salvador contra su segundo socio comercial más importante: la región centroamericana

Relación entre jarositas de ambientes naturales y sus análogos sintéticos

Depto. de Mineralogía y PetrologíaFac. de Ciencias GeológicasTRUEpu

Analysis of Different Uncertainty Activation Cross Section Data Libraries for LWR, ads and demo Neutron Spectra

This work is aimed to present the main differences of nuclear data uncertainties among three different nuclear data libraries: EAF-2007, EAF-2010 and SCALE-6.0, under different neutron spectra: LWR, ADS and DEMO (fusion

Influencia de las sustituciones isomórficas en los factores de estructura de hidroxisales de Co-Cu; Cu-Zn; Zn-Mg y Mg-Cu.

Depto. de Mineralogía y PetrologíaFac. de Ciencias GeológicasTRUEpu

Propiedades magnéticas de jarositas minerales y sintéticas

Depto. de Mineralogía y PetrologíaFac. de Ciencias GeológicasTRUEpu

First bird footprints from the lower Miocene Lerín Formation, Ebro Basin, Spain

A new tracksite with bird footprints, found in the Bardenas Reales de Navarra Natural Park (Navarre, Spain), is presented in this study. The footprints are preserved in four sandstone blocks of the Lerín Formation from the northwest sector of the Ebro Basin. According to the magnetostratigraphic data, the age of these blocks is 20.4 Ma (Agenian, lower Miocene). The footprints are more than 100 mm in length, mesaxonic, and tridactyl, and have a prominent central pad impression with the digit impressions not jointed proximally. These features allow classifying them as Uvaichnites riojana. Some of the studied footprints are better preserved than the type series of Uvaichnites, which were found also in the northwest sector of the Ebro Basin. Therefore, the original diagnosis has been emended. Available chronostratigraphic data for these localities as well as for other footprints from China indicate a latest Oligocene-earliest Miocene age (from about 23 to 20 Ma) for Uvaichnites-like footprints. Sedimentological data also indicate similar continental environments, namely perilacustrine deltaic systems and distal alluvial systems. The information about early Miocene avian remains (bones, eggs and footprints) in the Iberian Peninsula is scarce. The skeletal and oological record of this age has been included within the families Phoenicopteridae, Phaisanidae and Cathartidae (or incertae sedis), while the ichnological record was related with trackmakers belonging to Charadriiformes, Ardeidae and Gruidae taxa. For this scenario, in which there are few avian remains, the ichnological diversity shown in this paper complements and improves the knowledge about the Iberian avian diversity in the early Miocene

Angular emission properties of a layer of rare-earth based nanophosphors embedded in one-dimensional photonic crystal coatings

The angular properties of light emitted from rare-earth based nanophosphors embedded in optical resonators built in one-dimensional photonic crystal coatings are herein investigated. Strong directional dependence of the photoluminescence spectra is found. Abrupt angular variations of the enhancement caused by the photonic structure and the extraction power are observed, in good agreement with calculated polar emission patterns. Our results confirm that the optical cavity favors the extraction of different wavelengths at different angles and that integration of nanophosphors within photonic crystals provides control over the directional emission properties that could be put into practice in phosphorescent displays.Ministerio de Ciencia e Innovación MAT2008- 02166, CSD2007-00007Junta de Andalucía FQM3579, FQM524

Cost of energy and mutual shadows in a two-axis tracking PV system

The performance improvement obtained from the use of trackers in a PV system cannot be separated from the higher requirement of land due to the mutual shadows between generators. Thus, the optimal choice of distances between trackers is a compromise between productivity and land use to minimize the cost of the energy produced by the PV system during its lifetime. This paper develops a method for the estimation and optimization of the cost of energy function. It is built upon a set of equations to model the mutual shadows geometry and a procedure for the optimal choice of the wire cross-section. Several examples illustrate the use of the method with a particular PV system under different conditions of land and equipment costs. This method is implemented using free software available as supplementary material

Thamnophis eques (Mexican Garter Snake). Diet.

On 27 September 2018 at 1651 h, we captured an adult male T. eques that regurgitated a partially digested mouse pup. Analysis of rodent guard hair shows a lanceolate pattern of cuticular scales that is characteristic of Peromyscus melanotis. Our record increases the small mammals known to be consumed by snake T. eques to three species