Kinetics of the hydrogen electrode reaction on gold in acid sulphate melts

The hydrogen-electrode reaction on gold prepared in different ways has been investigated in molten acid sulphates at temperatures from ca 180 to 345°C. Potentiostatic and galvanostatic measurements under steady conditions were performed and the evolution of the potential of the working electrode when current was switched on and off was recorded. Current/voltage curves followed a Tafel law at cathodic overvoltages higher than 0-050 V. Slopes ranging from RT/2F to about 2RT/F are reported, depending on the preparation of the electrode, temperature and overvoltage region considered. Anodic current/voltage curves exhibit a limiting current. From the linear overvoltage/current region the reaction resistance was estimated for the anodic reaction. The exchange cds calculated from the reaction resistance agree with the values extrapolated from the Tafel lines having a slope RT/2F, if the stoichiometric number involved in the mechanism of the reaction is one. Electrode potential decayed logarithmically with time. Experimental electrode capacitances were evaluated from the time dependence of electrode potential. The hydrogen-electrode reaction is discussed in terms of a mechanism involving a fast hydrogenion discharge followed by a combination reaction as rate-determining step. The behaviour of the hydrogen-electrode reaction on gold in acid sulphate melts resembles that in aqueous acid solutions at ordinary temperatures.Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicada

La oración en los hechos de los apóstoles. Relación entre oración y evangelización

«En Cristo la oración se hacía vida y la vida se hacía oración» : Esta idea que Sett. Cipriani, gran conocedor del tema que hemos escogido para nuestro estudio, refleja continuamente en sus escritos, nos parace la introducción más apropiada para nuestro trabajo. Cuando dimos comienzo a nuestra investigación, partimos de una perspectiva bien determinada: considerar la oración de Jesús como el punto de partida y a su vez el ángulo visual para estudiar la oración de los primeros cristianos

Sectoral heterogeneity in patterns of educational mismatch in tourism: a gender comparison

The study of the effects of educational mismatch has shown this phenomenon to generate inefficiencies due to a misallocation of resources. These inefficiencies are more detrimental for countries such as Spain, where education is financed to a large extent with public funds, and low-skill demanding sectors, such as tourism, have a high weight in the economy. This paper aims to study the determinants of educational mismatch from a gender perspective, analysing the sectoral heterogeneity that may arise among these determinants in four key productive branches within the Spanish tourism sub-sector, i.e., hotels, transport, intermediary services and other complementary services. For this purpose, a multinomial logit model is employed, which will be estimated separately for each sector and gender of interest, using data from the 2018 Wage Structure Survey of the Spanish National Statistics Institute. Among the results obtained, it is highlighted, firstly, that educational mismatch is not a transitory phenomenon given that it occurs both at the beginning of the individual's working career and at very different levels of permanence. Secondly, it is interesting to note the greater probability of male overeducation observed in the hotel and catering industry and female overeducation in the rest of the services analysed, the latter result possibly reflecting the occupational gender segregation experienced by women in these branches of the economy.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

A comparative study of parallel software SURF implementations

Nowadays, it is common to find problems that require recognizing objects in an image, tracking them along time, or recognizing a complete real-world scene. One of the most known and used algorithms to solve these problems is the Speeded Up Robust Features (SURF) algorithm. SURF is a fast and robust local, scale and rotation invariant, features detector. This means that it can be used for detecting and describing a set of points of interest (keypoints) from an image. Because of the importance of this algorithm and the rise of the parallelism-based technologies, in the last years, diverse parallel implementations of SURF have been proposed. These parallel implementations are based on very different techniques: Compute Unified Device Architecture, OpenMp, OpenCL, and so on. In conclusion, we think valuable a comparative study of all of them highlighting the advantages and disadvantages of each parallel implementation. To our best knowledge, this article is the first attempt to do this comparative study. In order to make this study, we have used the standard metrics and image collection in this field, as well as other important metrics in parallelism as speedup and efficiency.ROMOCOG I and ROMOCOG II (TEP-4479 and TEP-6412) SpanishMinistry of Economy and Competitiveness and the ERDF (European Regional Development Fund), under the contract TIN2012-30685 (BIO project

Solving the multi-objective path planning problem in mobile robotics with a firefly-based approach

Currently, autonomous robotics is one of the most interesting and researched areas of technology. At the beginning, robots only worked in the industrial sector but, gradually, they started to be introduced into other sectors such as medicine or social environments becoming part of society. In mobile robots, the path planning (PP) problem is one of the most researched topics. Taking into account that the PP problem is an NP-hard problem, multi-objective evolutionary algorithms (MOEAs) are good candidates to solve this problem. In this work, a new multi-objective approach based on the flashing behavior of fireflies in nature, the multi-objective firefly algorithm (MO-FA), is proposed to solve the PP problem. This proposed algorithm is a swarm intelligence algorithm. The proposed MO-FA handles three different objectives to obtain accurate and efficient solutions. These objectives are the following: the path safety, the path length, and the path smoothness (related to the energy consumption). Furthermore, and to test the proposed MOEA, we have used eight realistic scenarios for the path’s calculation. On the other hand, we also compare our proposal with other approaches of the state of the art, showing the advantages of MO-FA. In particular, to evaluate the obtained results we applied specific quality metrics. Moreover, to demonstrate the statistical evidence of the obtained results, we also performed a statistical analysis. Finally, the study shows that the proposed MO-FA is a good alternative to solve the PP problem.Junta de Andalucía (Spain) ROMOCOG I and ROMOCOGII (P09-TEP-4479 and P10-TEP-6412). Spanish Ministry of Economy and Competitiveness and the ERDF (European Regional Development Fund), under the contract TIN2012-30685 (BIO project)

Uncertainty assessment for on-machine tool measurement: An alternative approach to the ISO 15530-3 technical specification

Touch probes are commonly employed in new machine tools (MTs), and enable machining and measuring processes to occur on the same MT. They offer the potential to measure components, either during or after the machining process, providing traceability of the quality inspection on the MT. Nevertheless, there are several factors that affect measurement accuracy on shop-floor conditions, such as MT geometric errors, temperature variation, probing system, vibrations and dirt. Thus, the traceability of a measurement process on an MT is not guaranteed and measurement results are therefore not sufficiently reliable for self-adapting manufacturing processes. The current state-of-the-art approaches employ a physically calibrated workpiece to realise traceable on-MT measurement according to the ISO 15530-3 technical specification, but it has a significant limitation in that it depends on a physical workpiece to understand the performance of the systematic error contributor (u b ). To this end, the aim of this paper is to propose an alternative methodology for on-MT uncertainty assessment without using a calibrated workpiece. The proposed approach is based on a volumetric error mapping of the MT prior to the measurement process, which provides an understanding of how the systematic error contributor(u b)performs

Kinetics of the hydrogen electrode reactionon gold in acid sulphate melts

The hydrogen-electrode reaction on gold prepared in different ways has been investigated in molten acid sulphates at temperatures from ca 180 to 345°C. Potentiostatic and galvanostatic measurements under steady conditions were performed and the evolution of the potential of the working electrode when current was switched on and off was recorded. Current/voltage curves followed a Tafel law at cathodic overvoltages higher than 0-050 V. Slopes ranging from RT/2F to about 2RT/F are reported, depending on the preparation of the electrode, temperature and overvoltage region considered. Anodic current/voltage curves exhibit a limiting current. From the linear overvoltage/current region the reaction resistance was estimated for the anodic reaction. The exchange cds calculated from the reaction resistance agree with the values extrapolated from the Tafel lines having a slope RT/2F, if the stoichiometric number involved in the mechanism of the reaction is one. Electrode potential decayed logarithmically with time. Experimental electrode capacitances were evaluated from the time dependence of electrode potential. The hydrogen-electrode reaction is discussed in terms of a mechanism involving a fast hydrogenion discharge followed by a combination reaction as rate-determining step. The behaviour of the hydrogen-electrode reaction on gold in acid sulphate melts resembles that in aqueous acid solutions at ordinary temperatures.Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicada

Phosphorylation-dependent regulation of the NOTCH1 intracellular domain by dual-specificity tyrosine-regulated kinase 2

NOTCH proteins constitute a receptor family with a widely conserved role in cell cycle, growing and development regulation. NOTCH1, the best characterised member of this family, regulates the expression of key genes in cell growth and angiogenesis, playing an essential role in cancer development. These observations provide a relevant rationale to propose the inhibition of the intracellular domain of NOTCH1 (Notch1-IC) as a strategy for treating various types of cancer. Notch1-IC stability is mainly controlled by post-translational modifications. FBXW7 ubiquitin E3 ligase-mediated degradation is considered one of the most relevant, being the previous phosphorylation at Thr-2512 residue required. In the present study, we describe for the first time a new regulation mechanism of the NOTCH1 signalling pathway mediated by DYRK2. We demonstrate that DYRK2 phosphorylates Notch1-IC in response to chemotherapeutic agents and facilitates its proteasomal degradation by FBXW7 ubiquitin ligase through a Thr-2512 phosphorylation-dependent mechanism. We show that DYRK2 regulation by chemotherapeutic agents has a relevant effect on the viability, motility and invasion capacity of cancer cells expressing NOTCH1. In summary, we reveal a novel mechanism of regulation for NOTCH1 which might help us to better understand its role in cancer biology

Impact of mandatory social isolation measures due to the COVID-19 pandemic on the subjective well-being of Latin American and Caribbean dentists

With the spread of the COVID-19 virus, containment measures such as home confinement were implemented, generating stress, anxiety, depression and aggravation of pre-existing diseases in the population, in- cluding dentists, who have also be

Anti-inflammatory and regenerative effects of MKARE® Eggshell Membrane: An in vitro osteoarthritis model and placebo-controlled clinical study

[EN]MKARE®, a 100% natural ingredient derived from fresh eggshell membrane (ESM), has a rich composition in bioactive compounds like collagen, hyaluronic acid, and elastin. These components are beneficial for managing osteoarthritis (OA) due to their anti-inflammatory and regenerative properties. Highlighting the significance of freshness, our research has shown that the effectiveness of MKARE® is higher than that of other commercial products based on ESM that have been stored for several days at room temperature, losing their bioactive compounds. This study explores the MKARE® anti-inflammatory capacity through an in vitro and clinical analyses, demonstrating its ability to alleviate OA symptoms and improve joint health. This underscores the crucial role of freshness in optimizing the therapeutic benefits.S