Na+-dependent NO3- uptake in leaf cells of the seagrass Posidonia oceanica (L.) Delile

Posidonia oceanica (L.) Delile is an endemic Mediterranean seagrass of recognized ecological significance and, as other seagrasses, this species has secondarily adapted to live in the marine environment. In this alkaline medium with a high Na+ concentration (0.5 M), the high inwardly directed electrochemical potential gradient for sodium is used in the seagrass Zostera marina to energize the uptake of nitrate1 and phosphate that usually occur at concentration below 10 µM. Here we summarize several evidences for the operation of a sodium-dependent high-affinity nitrate transport system at the plasma membrane of the mesophyll leaf cells of P. oceanica. Leaf cells of P. oceanica possess a H+-ATPase as a primary pump, exhibit a plasma membrane potential (Em) of -174 ± 10 mV and show reduced Na+ permeability. The addition of micromolar nitrate concentrations induces membrane depolarizations that show saturation kinetics. Curve fitting of the values renders a semisaturation constant (Km) of 21.3 ± 6.6 μM and a maximum depolarization (Dmax) of 7 ± 1 mV. In dark conditions, Dmax decreases by fifty percent but no significant effect is observed on the Km value. On the other hand, nitrate induced depolarizations show sodium dependence. The depolarizations induced by 100 µM NO3- in media containing increasing Na+ concentrations (from 0 to 250 mM) show saturation kinetics, rendering a Km value of 16 ± 5 mM Na+. Moreover, the depolarization induced by 100 µM NO3- is accompanied by a simultaneous increase of cytosolic sodium, measured by Na+-sensitive microelectrodes, of 0.4 ± 0.2 mM above the resting cytosolic sodium concentration (17 ± 2 mM). Finally, nitrate uptake rates, measured in depletion experiments, decreases by 50% and 80% in dark conditions and in the absence of Na+, respectively, compared with control conditions (0.5 M Na+ and light). All together, these results strongly suggest that NO3- uptake in P. oceanica leaf cells is mediated by a high-affinity nitrate carrier that uses Na+ as the driving ion. 1 Rubio et al. (2005). J. Exp. Bot, 412: 613-622. Project Funding: CTM 2011-30356. (MEC)Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

The problem of living in the sea: the uptake of inorganic carbon and nutrients in Posidonia oceanica (L.) Delile

The genus Posidonia exhibits a peculiar geographical distribution. It is composed by nine species, eight of which are distributed along the Australian coasts and only one, Posidonia oceanica (L.) Delile, is a Mediterranean endemism. Like other angiosperms, P. oceanica has adapted secondarily to the marine environment, and has developed anew mechanisms to face a liquid and alkaline medium (pH 8.2) that contains a high salt concentration (0.5 M NaCl). The liquid environment limits the diffusive flow of CO2 and nutrients and, furthermore, CO2 dissolves in water and forms HCO3-, the more abundant chemical species of inorganic carbon at pH 8.2. Like other green plants P. oceanica uses CO2 for photosynthesis. In addition, this species shows a transport system in the plasma membrane for the direct uptake of HCO3-, that uses H+ as the driving ion. The addition of HCO3- provokes a transient hyperpolarization of the plasma membrane followed by a depolarization; at the same time, the cytosolic pH (pHc) becomes transiently acidic and next it gets alkaline, and remains alkaline throughout the HCO3- pulse. The alkalinization of the pHc is due to the cytosolic accumulation of HCO3- and OH- and it is sensitive to the addition of ethoxyzolamide, an inhibitor of the internal carbonic anhydrase. The increase of negative charges in the cytosol triggers the release of Cl- to recover the values of the resting membrane potential. The plasmalemma of P. oceanica exhibits a reduced Na+ permeability and shows a H+/Na+ antiporter activity that keeps low and relatively constant the cytosolic Na+ concentration (17 mM Na+). The inside negative membrane potential (-178 mV) and the low [Na+]c generate a tremendous Na+-motive force that this plant uses for the high affinity transport of NO3- (Km= 21 µM), and of the amino acids alanine (Km= 37 µM) and cysteine (Km= 10 µM). The uptake of these compounds shows a strict dependence on the presence of Na+ in the medium. Moreover, the addition of micromolar concentrations of NO3-, alanine or cysteine gives rise to millimolar increments of [Na+]c. Experiments with external LIX pH mini-electrodes show that the uptake of glucose is not Na+ but H+ dependent. Thus, the model for the ion transport energization in this species seems to be mixed, with a H+-ATPase as the primary pump and a series of carriers that use H+ (HCO3-, Na+, glucose) or Na+ (NO3-, amino acids) as the driving ion. Project Funding: CTM 2011-30356 (MEC)Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Tratamiento de las enfermedades metabólicas en un hospital de tercer nivel

Las enfermedades de depósito lisosomal se originan por un déficit genético hereditario de determinadas enzimas lisosomales, lo que lleva a una acumulación de sustancias intermediarias del metabolismo en múltiples tejidos, ocasionando diversas patologías. Debido a su baja prevalencia, se consideran enfermedades raras, lo que dificulta en algunos casos un diagnóstico rápido. Este es fundamental debido a la gravedad de estas patologías y a su marcado carácter progresivo, cuyas consecuencias son una elevada letalidad y una corta esperanza de vida. El único tratamiento específico actual consiste en terapias de sustitución enzimática cuyo objetivo es suplir los déficits enzimáticos existentes. Dada la cronicidad y relevancia del tratamiento, es necesario un seguimiento exhaustivo de los pacientes con el objetivo de optimizar la respuesta terapéutica y monitorizar las posibles reacciones adversas al mismo. La aparición de la Terapia de Reemplazamiento Enzimático revolucionó las expectativas vitales de los pacientes y mejoró considerablemente su calidad de vida. Sin embargo, la aparición de tolerancias a la enzima exógena, las reacciones secundarias asociadas a su administración y su incapacidad de curar la enfermedad, impulsaron la búsqueda de nuevas estrategias terapéuticas. En los últimos años, además del uso de chaperonas farmacológicas asociadas a la enzima exógena para mejorar su eficacia, se han realizado numerosos estudios en animales además de ensayos clínicos. Todos ellos han puesto el foco en la terapia génica y podrían concluir en la comercialización de nuevos fármacos capaces de curar la enfermedad

Environmental analysis of university students’ mode of transportation and paper consumption

Las actividades que se desarrollan en las organizaciones educativas tienen un determinado impacto ambiental. Analizar el efecto de las mismas sobre el medio ambiente permite determinar y priorizar acciones para minimizarlo. Una forma de cuantificarlo es mediante el indicador ambiental Huella Ecológica que tiene un alto potencial como herramienta de concientización.Este tipo de organizaciones presentan un alto consumo de papel. Además, la movilidad de la comunidad hacia las sedes en las cuales se realizan las actividades académicas involucra un uso intensivo de transporte (trenes, subte, colectivos, bicicletas y autos particulares). Con el objetivo de calcular el indicador Huella Ecológica se realizó una encuesta a estudiantes de la asignatura Análisis Matemático II de la Facultad de Ciencias Económicas de la Universidad de Buenos Aires para determinar el consumo de papel y el tipo de movilidad utilizada para asistir a clase. Con estos datos, se calculó el impacto ambiental de dicha actividad.En este trabajo se describe la metodología utilizada y se presentan los resultados obtenidos sobre estos dos aspectos ambientales: consumo de papel y transporte estudiantil.The activities undertaken in educational organizations have a certain environmental impact. Analyzing their effect on the environment makes it possible to determine and prioritize actions aimed at minimizing it. One way to quantify such effect is by means of the Ecological Footprint environmental indicator, which has a high potential when used as an awareness-raising tool. These types of organizations have a high level of paper consumption. In addition, students commute to their campuses, thus involving an intensive use of transport systems (trains, subway, buses, bicycles, and private cars). In order to calculate the Ecological Footprint indicator, a survey responded to by students of the ‘Mathematical Analysis II’ subject at the School of Economics of the Universidad de Buenos Aires was carried out, so as to determine their paper consumption and the mode of transportation used to attend their classes. Based on these data, the environmental impact of this activity was calculated. This paper describes the methodology used and presents the results obtained for these two environmental aspects: paper consumption and students’ transport.Fil: Fernandez, María José. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Instituto Interdisciplinario de Economía Política de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Económicas. Instituto Interdisciplinario de Economía Política de Buenos Aires; ArgentinaFil: García Fronti, Verónica. Universidad de Buenos Aires. Facultad de Cs.económicas. Instituto de Invest.en Adm Contab y Met Cuant P/gestion; ArgentinaFil: Parma, Andrea. Universidad de Buenos Aires. Facultad de Ciencias Económicas. Instituto de Investigación en Administración, Contabilidad y Matemática. Centro de Investigación en Metodologías Básicas y Aplicadas a la Gestión y Economía; Argentin

La eficiencia en el sector de las agencias de publicidad

El principal objetivo de este trabajo es estudiar la eficiencia de las agencias de publicidad en España, para lo cual hemos estimado una frontera de producción estocástica Translog con los datos proporcionados por la base de datos SABI (Sistema de Análisis de Balances Ibéricos). Hemos observado que el sector se compone, principalmente, de microempresas y está muy concentrado en Madrid y Cataluña, comunidades en las que están registradas más de la mitad de las agencias de la muestra. Con respecto a la eficiencia del sector, encontramos que, en media, es relativamente elevada, siendo las empresas pertenecientes a La Rioja y Navarra las más eficientes, frente a las de Castilla y León, Comunidad Valenciana y País Vasco, comunidades con una eficiencia por debajo de la media. Por último, destacar que los resultados obtenidos sugieren que el tamaño de las empresas ejerce una influencia negativa sobre las eficiencias en las agencias de publicidad. <br /

Extendiendo ABP con feedback ágil en la enseñanza de Ingeniería del Software

El Aprendizaje Basado en Proyectos (ABP) ha sido aplicado con éxito en diversas áreas de la docencia de la informática en el ámbito universitario. A su vez, a nivel industrial en el contexto de la ingeniería del software, las metodologías ágiles se han instaurado como la opción más utilizada para el desarrollo de proyectos gracias en parte a su promoción de un feedback temprano y continuo que ayuda a enfocar y adaptar el desarrollo a las necesidades del cliente. Este artículo presenta una experiencia piloto que aúna ambos conceptos, extendiendo el enfoque ABP para incorporar el ciclo de feedback rápido y continuo de las metodologías ágiles en la docencia de ingeniería del software. Dicho ciclo se incorpora mediante la aplicación de una evaluación continua de las tareas realizadas por el alumno, en base a un backlog de tareas semanales y a listas de verificación que permiten evaluar el trabajo realizado de manera objetiva. Los resultados obtenidos son prometedores, tanto en términos de la distribución de notas de los alumnos como en cuanto a la motivación de los alumnos con asignatura. Finalmente, se ha realizado un análisis pormenorizado de las numerosas métricas recolectadas de las distintas plataformas utilizadas que ha permitido un estudio de las tipologías de alumnos y la obtención de un conjunto de lecciones aprendidas que pueden ser aplicadas en el diseño de experiencias docentes similares.Project Based Learning (PBL) has been successfully applied in a number of scenarios as part of the Computer Science teaching. Alternatively, from the software industry point of view, agile methodologies represent a first class citizen being the most suitable choice in several cases as they boost an early customer feedback so it can be adapted to its needs. This paper presents a first experience combining PBL and Agile methodologies in Software Engineering course. Specifically, our approach combines the usage of a weekly backlog with a peer-reviewing process based on checklists that allow an accurate continuous evaluation of students performance. The results analysis of our experience shows an appropriate distribution of scores and a significant improvement in the student motivation. Additionally, we detail the analysis of a number of metrics in order to characterize some students patterns that support a list of lessons learned to potentially improve the teaching in similar courses

Modelling the energy harvesting from ceramic-based microbial fuel cells by using a fuzzy logic approach

© 2019 The Author(s) Microbial fuel cells (MFCs) is a promising technology that is able to simultaneously produce bioenergy and treat wastewater. Their potential large-scale application is still limited by the need of optimising their power density. The aim of this study is to simulate the absolute power output by ceramic-based MFCs fed with human urine by using a fuzzy inference system in order to maximise the energy harvesting. For this purpose, membrane thickness, anode area and external resistance, were varied by running a 27-parameter combination in triplicate with a total number of 81 assays performed. Performance indices such as R2 and variance account for (VAF) were employed in order to compare the accuracy of the fuzzy inference system designed with that obtained by using nonlinear multivariable regression. R2 and VAF were calculated as 94.85% and 94.41% for the fuzzy inference system and 79.72% and 65.19% for the nonlinear multivariable regression model, respectively. As a result, these indices revealed that the prediction of the absolute power output by ceramic-based MFCs of the fuzzy-based systems is more reliable than the nonlinear multivariable regression approach. The analysis of the response surface obtained by the fuzzy inference system determines that the maximum absolute power output by the air-breathing set-up studied is 450 μW when the anode area ranged from 160 to 200 cm2, the external loading is approximately 900 Ω and a membrane thickness of 1.6 mm, taking into account that the results also confirm that the latter parameter does not show a significant effect on the power output in the range of values studied

Evaluation of artificial neural network algorithms for predicting the effect of the urine flow rate on the power performance of microbial fuel cells

© 2020 The Authors Microbial fuel cell (MFC) power performance strongly depends on the biofilm growth, which in turn is affected by the feed flow rate. In this work, an artificial neural network (ANN) approach has been used to simulate the effect of the flow rate on the power output by ceramic MFCs fed with neat human urine. To this aim, three different second-order algorithms were used to train our network and then compared in terms of prediction accuracy and convergence time: Quasi-Newton, Levenberg-Marquardt, and Conjugate Gradient. The results showed that the three training algorithms were able to accurately simulate power production. Amongst all of them, the Levenberg-Marquardt was the one that presented the highest accuracy (R = 95%) and the fastest convergence (7.8 s). These results show that ANNs are useful and reliable tools for predicting energy harvesting from ceramic-MFCs under changeable flow rate conditions, which will facilitate the practical deployment of this technology

Elebakarren eta elebidunen euskararen jabekuntzaren erritmoaren inguruan

The present study examines the relationship between the linguistic input heard by children and their linguistic development in order to ascertain if the amount of input to which a child is exposed is a determining factor for the onset of language development.The development of Basque was studied in a sample of 950 children aged between 16 and 30 months who were exposed to different amounts of the language in the following proportions: A. monolingual children who only or mostly heard Basque (90-100% of input in Basque), B. bilingual children with high exposure to Basque (60-90% of input in Basque), C. bilingual children with largely equal amounts of exposure to Basque and another language (40-60% of input in Basque) D. bilingual children with low levels of exposure to Basque (less than 40% exposure to Basque).Development in vocabulary, morphology and syntax were analysed in the four groups at different ages. The groups were formed on the basis of parental report obtained by using the adaptation into Basque of the MacArthur Bates Communicative DeveLopment Inventories.The results show that up until the age of 26 months there are no significant differences between the four groups and that these can only be seen when children who only hear Basque, or who have a high degree of exposure to it (more than 60% of the time) are compared with those children with less exposure to Basque (less than 60% of the time)

Desarrollo de procedimientos y técnicas contra Sistemas Aéreos No Tripulados

En la actualidad, en comparación con la última década, el uso de sistemas aéreos no tripulados ha aumentado de forma exponencial. Estos se encuentran al alcance de cualquier usuario debido a la gran oferta en el mercado. Tampoco facilita el control de los mismos su bajo coste y la posibilidad de poder comprarlos sin ningún tipo de licencia.Además, se han aprovechado de estas nuevas tecnologías para emplearlas con fines hostiles o maliciosos los agentes estatales y no estatales. Estos sistemas aéreos no tripulados de pequeño tamaño, que vuelan a baja altura, son difíciles de identificar, detectar y neutralizar por los medios actuales de Defensa Aérea. Debido a esto, suponen una gran amenaza para nuestras FAS, tanto en territorio nacional como para las tropas desplegadas en misiones en el exterior, así como para el resto de los ciudadanos.Nos estamos enfrentando a una amenaza para la seguridad, es por ello la importancia de este trabajo, en el cual, analizando el estado del arte tanto de los sistemas aéreos no tripulados como de sus contramedidas, se propondrán unos procedimientos y técnicas para enfrentarse a esa amenaza.<br /