2,488 research outputs found
Experimental Quantification of the Effect of Nonlinearities on the EIS Spectra of the Cathodic Electrode of an Alkaline Electrolyzer
[EN] Electrochemical impedance spectroscopy (EIS) is a very powerful tool to study the behavior of electrochemical systems. According to Ohm¿s generalized law, the impedance concept is only valid if the linearity condition is met. In the case that the linearity condition is not achieved, the obtained impedance spectra will present distortions which may lead to biased or even erroneous results and conclusions. In this work, an experimental quantification of the effect of nonlinearities on EIS spectra was performed in order to determine
the order of magnitude of the effect of the nonlinearity of the system on the obtained spectra of the cathodic electrode of an alkaline electrolyzer.The authors are very grateful to the Generalitat Valenciana for its economic support in form of Vali+d grant (Ref: ACIF-2013-268).Giner-Sanz, J.; Ortega, E.; Pérez-Herranz, V. (2017). Experimental Quantification of the Effect of Nonlinearities on the EIS Spectra of the Cathodic Electrode of an Alkaline Electrolyzer. Fuel Cells. 17(3):391-401. https://doi.org/10.1002/fuce.201600137S39140117
Mineral composition of bee pollen and its relationship with botanical origin and harvesting period
Producción CientíficaIn the present study, the mineral composition of seventy-one bee pollen samples from four different apiaries was determined by means of inductively coupled plasma-optical emission spectrometry. The results showed that there were no significant differences in relation to the overall mineral content per sample in terms of the apiary of origin or the harvesting period; the most common elements were phosphorus and potassium with concentrations ranging from 2.3 to 5.1 g/kg (dry weight). Moreover, the mineral content of the samples analyzed was similar to or higher than the recommended as well-balanced food for bees. Regarding the nutritional value for humans, bee pollen samples could be considered as a food rich in copper, iron, magnesium, manganese, and phosphorus. Finally, a canonical discriminant analysis was performed, and it was found that the apiary of origin could be distinguished by using the first three canonical functions; furthermore, over 90% of the samples could be correctly assigned to their corresponding apiary. The results were even better as regards the harvesting period, as only the first two canonical functions were sufficient to make a distinction between the different harvesting periods, resulting in a perfect match (100% of success rate).Ministerio de Economía y Competitividad (RTI2018-096268-B-100)Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (RTA 2015-00013-C03-01 and 03)FEDER and FSE (project AGRISOST-CM S2018/BAA-4330
Bayesian Networks for Decision-Making and Causal Analysis under Uncertainty in Aviation
Most decisions in aviation regarding systems and operation are currently taken under uncertainty, relaying in limited measurable information, and with little assistance of formal methods and tools to help decision makers to cope with all those uncertainties. This chapter illustrates how Bayesian analysis can constitute a systematic approach for dealing with uncertainties in aviation and air transport. The chapter addresses the three main ways in which Bayesian networks are currently employed for scientific or regulatory decision-making purposes in the aviation industry, depending on the extent to which decision makers rely totally or partially on formal methods. These three alternatives are illustrated with three aviation case studies that reflect research work carried out by the authors
Estructura europea para la supervisión y el seguimiento de hábitats: aproximación metodológica para España
There is a well defined policy requirement for a practical and reproducible procedure for surveillance and monitoring of habitats in Spain that can subsequently be fitted into a European framework. Any such procedure also needs to incorporate records of the Spanish habitat classification. A procedure is described that will satisfy those requirements and has been field tested both in Spain and in Europe. Rigorous rules and training are required; otherwise changes from baseline records cannot reliably be separated from background noise. The procedure uses the classical plant life forms long used in biogeography and is based on their statistical relationship with the environment. This relationship has been validated statistically and the procedure has also been tested in the field in all European environmental zones and widely in Spain. 130 General Habitat Categories are defined and these are enhanced in the field by recording environmental, site and management qualities to produce a flexible database that can then be interrogated. The rules for mapping the habitats mean that they can be used for descriptive purposes or for monitoring. In conjunction with stratification and subsequent sampling, national estimates of stock and change can then be produced. Finally, based on the previous experience of SISPARES, a methodological scheme is proposed for adapting the approach to Spain. The proposal will allow links to be made between European scale surveillance and monitoring to those already obtained for Spain.en España políticas bien definidas que demandan procedimientos prácticos y reproducibles para llevar a cabo la supervisión y seguimiento de los hábitats, de modo que subsecuentemente puedan ajustarse al marco Europeo. Cualquier procedimiento de estas características necesita poder incorporar datos registrados de la clasificación española de hábitats. Aquí se describe un procedimiento que satisface dichos requisitos y que ha sido probado tanto en España como en el resto de Europa. El método exige reglas rigurosas y entrenamiento de campo; si no los cambios en los registros básicos no se podrán separar de manera fiable de los errores subjetivos cometidos durante la toma de datos. El procedimiento utiliza las clásicas formas de vida, ampliamente utilizadas en estudios biogeográficos y está basado en sus relaciones con el medio ambiente. Esta relación ha sido validada estadísticamente y el procedimiento ha sido probado en el campo en todas las zonas ambientales de Europa. En España, se han definido 130 Categorías Generales de Hábitats y se han verificado en el campo mediante el registro de atributos ambientales, estacionales y de manejo, de forma que puedan ser incluidas en una base de datos suficientemente flexible. Las directrices para la cartografía de hábitats posibilitan su uso descriptivo y permiten su seguimiento. Al mismo tiempo, con la estratificación y subsecuente muestreo, es posible hacer estimaciones nacionales de existencias y de cambios Finalmente, basados en las experiencias previas de SISPARES, se propone un esquema metodológico para adaptar BIOHAB a España. La propuesta permitirá conectar los resultados a escala Europea de supervisión y seguimiento con los obtenidos a escala española
Abnormal quality detection and isolation in water distribution networks using simulation models
This paper proposes a model based detection and localisation method to deal with abnormal quality levels based on the chlorine measurements and chlorine sensitivity analysis in a water distribution network. A fault isolation algorithm which correlates on line the residuals (generated by comparing the available chlorine measurements with their estimations using a model) with the fault sensitivity matrix is used. The proposed methodology has been applied to a District Metered Area (DMA) in the Barcelona network
Nd3+-doped TeO2–PbF2–AlF3 glasses for laser applications
A study of the optical properties of Nd3+ ion in TeO2–PbF2–AlF3 glasses has been carried out for different
Nd3+ concentrations. Based on the Judd–Ofelt theory, intensity parameters and radiative properties were
determined from the absorption spectra. Focusing on the suitability of this host for laser applications, the
spectroscopic quality factor v was obtained with a value of 1.07, a value of the order of other
compositions proposed as laser hosts. For the most intense emission corresponding with the
4F3/2?4I11/2 transition (1.06 lm), the absorption and emission and have been calculated with values
of 1.20 10 20 cm2, 2.08 10 20 cm2. A positive value for the gain cross-sections has been found for a
population inversion factor c of 0.4 in the spectral range from 1060 to 1110 nm. All these results suggest
the potentially use of this system as a laser host
El sentimiento relacional de género en el alumnado de Educación Secundaria Obligatoria
Esta comunicación presenta resultados empíricos sobre la preferencia relacional del
alumnado en la Educación Secundaria Obligatoria. Mediante el instrumento Escala de
Preferencias Relacionales de Género se indaga en las predisposiciones del alumnado a elegir
o rechazar a chicos o chicas según el tipo de actividad conjunta a desarrollar. Según las
elecciones o los rechazos constatados podemos conocer acerca de la presencia de los
mandatos de género en las aulas escolares. La muestra se compone de 722 estudiantes
(chicas y chicos = 50%) de E.S.O. de la provincia de Sevilla. El error muestral es de 3,7%
con un nivel de confianza del 95,5% con la máxima varianza proporcional (p = q). Los
resultados muestran algunas pautas de elección según el género, observándose que las chicas
son más elegidas para compartir secretos o los chicos para practicar deporte, lo que nos
permite concluir sobre la presencia en la escuela de los mandatos de género patriarcales.This paper presents empirical results on relational preference of students in secondary
education. The instrument Relational Scale for Gender Preferences explores students'
predispositions to choose or refuse to boys or girls under the joint activity to develop.
According to the observed choices or rejections can know about the presence of gender
mandates in the classroom. The sample consists of 722 students (girls and boys = 50%) of
ESO in the province of Seville. The sampling error is 3.7% with a confidence level of 95.5%
with maximum variance method (p = q). The results show some patterns of choice by gender,
showing that girls are chosen to share secrets or the kids to play sports, allowing us to
conclude about the presence in the school of patriarchal gender mandates
Lifestyle and fat distribution in asthmatic and healthy adolescents
Introducción: el objetivo es analizar el estilo de vida, en función del ejercicio y la dieta, de un grupo de adolescentes de la Comunidad de Madrid, teniendo en cuenta género y patología y su relación con el estado nutricional, la distribución de grasa y la función pulmonar. Metodología: Estudio descriptivo de 207 sujetos que analizó el estilo de vida a partir del nivel de actividad física (AF) y la adherencia a la dieta mediterránea, el estado nutricional y la distribución de grasa, y la salud respiratoria. Resultados: El grupo de no asmáticos fue más activo (p=0,003) y presentó menor ICT (p=0,001) que el grupo de asmáticos. Se encontraron diferencias significativas dentro del grupo sin asma en nivel de AF siendo los varones más activos (p=0,01) y presentando menor índice cintura-talla (ICT) que las mujeres del mismo grupo (p=0,001). Conclusiones: Los adolescentes no asmáticos fueron más activos y presentaron mejor distribución de grasa que los asmáticosObjectives: objective is to analyze the lifestyle, integrating exercise and diet, of a group of adolescents from the Community of Madrid, taking into account gender and pathology and its relationship with nutritional status, fat distribution and lung function in adolescents with or without asthma. Methods: This was a descriptive study including 207 subjects aged 13.20 ± 0.62 years. Lifestyle was assessed in terms of physical activity (PA) levels, Mediterranean diet, nutritional status, and respiratory health measured through FEV1 (z). Results: In the non-asthma group, boys were more active (p = 0.01) and showed a lower waist-to-height ratio (WHtR) than girls (p = 0.001). Participants without asthma were more active (p = 0.003), and had a better WHtR (p = 0.001) and FEV1 (p = 0.001) than those with asthma. Conclusions: In this Spanish population sample, non-asthmatic adolescents were more active and showed a better nutritional status, fat distribution and respiratory health than their peers with asthmaFinanciado a través de la VII Convocatoria Real Madrid-Universidad Europea (Ref 2015/03RM); Tercer premio en los XV Premios Neumomadrid; Beca Jóvenes Investigadores de la SENP 2015
Supporting data for the MS identification of distinct transferrin glycopeptide glycoforms and citrullinated peptides associated with inflammation or autoimmunity
This data article presents the results of all the statistical analyses applied to the relative intensities of the detected 2D-DiGE protein spots for each of the 3 performed DiGE experiments. The data reveals specific subsets of protein spots with significant differences between WT and CD38-deficient mice with either Collagen-induced arthritis (CIA), or with chronic inflammation induced by CFA, or under steady-state conditions. This article also shows the MS data analyses that allowed the identification of the protein species which serve to discriminate the different experimental groups used in this study. Moreover, the article presents MS data on the citrullinated peptides linked to specific protein species that were generated in CIA(+) or CFA-treated mice. Lastly, this data article provides MS data on the efficiency of the analyses of the transferrin (Tf) glycopeptide glycosylation pattern in spleen and serum from CIA(+) mice and normal controls. The data supplied in this work is related to the research article entitled "identification of multiple transferrin species in spleen and serum from mice with collagen-induced arthritis which may reflect changes in transferrin glycosylation associated with disease activity: the role of CD38" [1]. All mass spectrometry data have been deposited to the ProteomeXchange Consortium via the PRIDE partner repository with identifiers PRIDE: PXD002644, PRIDE: PXD002643, PRIDE: PXD003183 and PRIDE: PXD003163
Tracing sulfate recycling in the hypersaline Pétrola lake (SE Spain): A combined isotopic and microbiological approach
Sulfur (S) plays a significant role in saline environments, and sulfate (SO4 2−) is an important component of the biogeochemical S-cycle since it acts as the main electron acceptor in anoxic sediments. The purpose of this paper is to evaluate the fate of S, its origin, and processes affecting sulfate outcome in the hypersaline Pétrola Lake in the Castilla-La Mancha region (High Segura Basin, SE Spain). The lake is the terminal discharge zone of an endorheic basin with considerable anthropogenic pressures. Anthropogenic activities (mainly agricultural inputs and wastewater discharge), together with bedrock leaching of sulfate and sulfide-rich sediments, increase dissolved SO4 2− in surface and groundwater up to 123,000 mg/L. The source and fate of sulfate in this environment was investigated coupling hydrochemistry, including hydrogen sulfide (H2S) microprofiles, isotopic analyses (δ34S, δ18OSO4, δ2HH2O, δ18OH2O, and tritium), mineralogical determinations, and molecular biology tools (16S rDNA amplification and sequencing). The origin of dissolved SO4 2− in water is related to pyrite oxidation from Lower Cretaceous sediments, and secondary gypsum dissolution. Under the lake, dissolved SO4 2− decreases with depth, controlled by three main processes: (1) seasonal evaporation cycles, (2) hydrodynamic instability caused by the different density-driven groundwater flow, and (3) sulfate-reduction processes, i.e. dissimilatory bacterial sulfate reduction (BSR). These processes control the continuous recycling of sulfur in the system. Lake water and groundwater are in hydraulic connection, and a density-driven flow (DDF) is able to transport reactive organic matter and dissolved SO4 2− towards the underlying aquifer. Hydrochemical evolution in depth, H2S production (up to 0.024 nmol/cm3·s) and the presence of sulfate-reducing bacteria suggest the existence of BSR processes. However, isotope techniques are insufficient to elucidate BSR processes since their isotopic effect is masked by low isotope fractionation and high SO4 2− concentrations. The pattern here described may be found in other saline basins worldwide
- …