Nitrogen loss processes in response to upwelling in a Peruvian coastal setting dominated by denitrification – a mesocosm approach

Upwelling of nutrient-rich deep waters make eastern boundary upwelling systems (EBUSs), such as the Humboldt Current system, hot spots of marine productivity. Associated settling of organic matter to depth and consecutive aerobic decomposition results in large subsurface water volumes being oxygen depleted. Under these circumstances, organic matter remineralisation can continue via denitrification, which represents a major loss pathway for bioavailable nitrogen. Additionally, anaerobic ammonium oxidation can remove significant amounts of nitrogen in these areas. Here we assess the interplay of suboxic water upwelling and nitrogen cycling in a manipulative offshore mesocosm experiment. Measured denitrification rates in incubations with water from the oxygen-depleted bottom layer of the mesocosms (via 15N label incubations) mostly ranged between 5.5 and 20 nmol N2 L−1 h−1 (interquartile range), reaching up to 80 nmol N2 L−1 h−1. However, actual in situ rates in the mesocosms, estimated via Michaelis–Menten kinetic scaling, did most likely not exceed 0.2–4.2 nmol N2 L−1 h−1 (interquartile range) due to substrate limitation. In the surrounding Pacific, measured denitrification rates were similar, although indications of substrate limitation were detected only once. In contrast, anammox (anaerobic ammonium oxidation) made only a minor contribution to the overall nitrogen loss when encountered in both the mesocosms and the Pacific Ocean. This was potentially related to organic matter C / N stoichiometry and/or process-specific oxygen and hydrogen sulfide sensitivities. Over the first 38 d of the experiment, total nitrogen loss calculated from in situ rates of denitrification and anammox was comparable to estimates from a full nitrogen budget in the mesocosms and ranged between ∼ 1 and 5.5 µmol N L−1. This represents up to ∼  20 % of the initially bioavailable inorganic and organic nitrogen standing stocks. Interestingly, this loss is comparable to the total amount of particulate organic nitrogen that was exported into the sediment traps at the bottom of the mesocosms at about 20 m depth. Altogether, this suggests that a significant portion, if not the majority of nitrogen that could be exported to depth, is already lost, i.e. converted to N2 in a relatively shallow layer of the surface ocean, provided that there are oxygen-deficient conditions like those during coastal upwelling in our study. Published data for primary productivity and nitrogen loss in all EBUSs reinforce such conclusion

Framework para la generación de templates en sistemas de catálogos de realidad aumentada

En este trabajo presentamos el desarrollo de un sistema de aumentación de metacontenidos sobre las bases del sistema de catálogo virtuales aumentados a fin de mejorar la usabilidad del sistema original para usuarios no expertos. Se propone pues la incorporación del concepto de template de aumentación de la realidad, para los catálogos de realidad aumentada. Los mismos permitirán predefinir la cantidad y tipos de contenidos, junto con sus transformaciones geométricas y el orden en el que aparecen en un determinado template. Así, al aplicarlo a un catálogo aumentado ayudará a mantener un formato uniforme entre todos sus marcadores, así como también simplificará la carga del material a aumentar por parte de usuarios no expertos en el área.Eje: Computación Gráfica, Imágenes y Visualización.Red de Universidades con Carreras en Informática (RedUNCI

Herramienta de Realidad Aumentada para Facilitar la Enseñanza en Contextos Educativos Mediante el Uso de las TICs

La Realidad Aumentada agrega elementos virtuales al entorno Real, proporcionándonos información de interés para el usuario aprovechando la infraestructura de las TICs. De esta manera, el entorno real es enriquecido con información mejorando así las experiencias en diferentes áreas, tales como entretenimiento, salud, Industria y principalmente los entornos educativos. En este artículo se presenta un framework que facilite a los educadores la enseñanza de los contenidos y aumente la participación de los alumnos, usando un juego de mesa. De esta manera, el alumnado interactúa directamente con los contenidos virtuales con el fin de afianzar sus conocimientos en diferentes áreas

BiosecurID: a multimodal biometric database

A new multimodal biometric database, acquired in the framework of the BiosecurID project funded by the Spanish MEC, is presented together with a brief description of the acquisition setup and protocol. The database includes 7 unimodal biometric traits, namely: speech, iris, face (photographs and talking faces), signature and handwriting (online and off-line), fingerprints (acquired with two different sensors), hand (palmprint and contour-geometry) and keystroking. The database comprises 400 subjects and presents features such as: realistic acquisition scenario, balanced gender and population distributions, availability of information about particular demographic groups (age, gender, handedness), acquisition of skilled forgeries, and compatibility with other existing databases. All these characteristics make it very useful in research and development of multimodal biometric systems