Optimización del Tratamiento Térmico de Productos Tubulares de Acero

[Optimization of Heat Treatment of Steel Tubular Products] El problema a abordar es el de la optimización del tratamiento térmico de productos tubulares de acero, presente en la empresa siderúrgica Tenaris. Más específicamente, se estudia el problema de dar un tratamiento adecuado a cargas retenidas en el horno de revenido. En este caso, el tratamiento térmico se compone de un primer calentamiento de los tubos a temperaturas cercanas a los 900°C, en el que se austeniza el material, seguido por un enfriamiento rápido en el que el material se transforma en martensita. Esta etapa constituye el templado del acero. Para lograr las propiedades metalúrgicas finales especificadas para el producto se realiza un segundo calentamiento a temperaturas entre 500 y 700°C, que se denomina revenido. Para simplificar el análisis, en este trabajo se considera una única propiedad metalúrgica, la dureza, que para el producto que se analiza debe estar en el rango de 270-300 Hv

Allocation of endogenous and dietary protein in the reconstitution of the gastrointestinal tract in migratory blackcaps at stopover sites

During migratory flight, the mass of the gastrointestinal tract (GIT) and its associated organs in small birds decreases in size by as much as 40%, compared with the preflight condition because of the catabolism of protein. At stopover sites, birds need 2–3 days to rebuild their GIT so that they can restore body mass and fat reserves to continue migration. The source of protein used to rebuild the GIT may be exogenous (from food ingested) or endogenous (reallocated from other organs) or both. Because the relative contribution of these sources to rebuild the GIT of migratory birds is not yet known, we mimicked in-flight fasting and then re-feeding in two groups of blackcaps (Sylvia atricapilla), a Palearctic migratory passerine. The birds were fed a diet containing either 3% or 20% protein to simulate different refueling scenarios. During re-feeding, birds received known doses of 15N-l-leucine before we measured the isotope concentrations in GIT and associated digestive organs and in locomotory muscles. We then quantified the extent to which blackcaps rebuilt their GIT with endogenous and/or dietary protein while refeeding after a fast. Our results indicate that blackcaps fed the low-protein diet incorporated less exogenous nitrogen into their tissues than birds fed the 20% protein diet. They also allocated relatively more exogenous protein to the GIT than to pectoral muscle than those birds re-fed with the high-protein diet. However, this compensation was not sufficient for birds eating the low-protein diet to rebuild their intestine at the same rate as the birds re-fed the high-protein diet. We concluded that blackcaps must choose stopover sites at which they can maximize protein intake to minimize the time it takes to rebuild their GIT and, thus, resume migration as soon as possible

The importance of the lipoxygenase-hepoxilin pathway in the mammalian epidermal barrier

This review covers the background to discovery of the two key lipoxygenases (LOX) involved in epidermal barrier function, 12R-LOX and eLOX3, and our current views on their functioning. In the outer epidermis, their consecutive actions oxidize linoleic acid esterified in ω-hydroxy-ceramide to a hepoxilin-related derivative. The relevant background to hepoxilin and trioxilin biochemistry is briefly reviewed. We outline the evidence that linoleate in the ceramide is the natural substrate of the two LOX enzymes and our proposal for its importance in construction of the epidermal water barrier. Our hypothesis is that the oxidation promotes hydrolysis of the oxidized linoleate moiety from the ceramide. The resulting free ω-hydroxyl of the ω-hydroxyceramide is covalently bound to proteins on the surface of the corneocytes to form the corneocyte lipid envelope, a key barrier component. Understanding the role of the LOX enzymes and their hepoxilin products should provide rational approaches to ameliorative therapy for a number of the congenital ichthyoses involving compromised barrier function. This article is part of a Special Issue entitled The Important Role of Lipids in the Epidermis and their Role in the Formation and Maintenance of the Cutaneous Barrier. Guest Editors: Kenneth R. Feingold and Peter Elias

Diversidad genética de las razas porcinas ibérica y alentejana mediante el genotipado de variantes genéticas en genes mayores y genes candidatos

Las razas porcinas ibérica y alentejana se encuentran biogeográficamente localizadas en el suroeste de la península Ibérica. Estas razas comparten un conjunto de características comunes. Ambas son fenotípicamente muy similares; muestran un bajo índice de crecimiento y una elevada deposición grasa y tienen un sistema común de producción al aire libre en el que se explotan los recursos de la Dehesa. El objetivo del presente trabajo, dentro del marco del proyecto TREASURE, consistió en caracterizar la diversidad genética de ambas razas usando los datos de genotipado de 39 polimorfismos localizados en 34 genes previamente asociados a distintos caracteres de interés económico. Estos polimorfismos fueron genotipados en 950 cerdos pertenecientes a las razas ibérica y alentejana y a 18 razas europeas autóctonas adicionales. Los bajos valores para heterozigosidad observada y esperada indican una baja diversidad genética en ibéricos y alentejanos. Las distancias genéticas estimadas usando DS y FST fueron cercanas a 0 (0.007 y 0.039, respectivamente), sugieren que estas razas son genéticamente muy similares. Asimismo, las técnicas de análisis multivariante utilizadas como análisis de componentes principales y asignación a grupos mostraron que los individuos de estas razas están muy próximos formando clusters diferenciados del resto de razas. Estos resultados concuerdan con los de otros autores que ya mostraron distancias genéticas cortas entre ambas razas usando secuencias de ADN mitocondrial

La plataforma siette una herramienta para el aprendizaje de la botánica forestal

El avance tecnológico está incorporando nuevas herramientas de aprendizaje para complementar el estudio y realizar prácticas de autoevaluación de valor formativo, ya que mediante el ejercicio de evaluación el estudiante puede reflexionar sobre su progreso y dirigir mejor su esfuerzo en el estudio. En este marco la plataforma SIETTE es un sistema web que permite la creación y mantenimiento de bancos de preguntas, y realización de tests, que implementa la Teoría Clásica de Test (CTT), Teoría de Respuesta al Ítem (TRI), permite realizar Tests Adaptativos Informatizados (TAI), y puede usarse como herramienta para el aprendizaje colaborativo. Siette puede usarse como módulo de evaluación de un Sistema Tutor Inteligente (STI) o conectado a una Plataforma de Teleeducación (LMS) como Moodle. Siette implementa muchas otras opciones para la realización de prácticas de reconocimiento, repaso, y evaluación. Esta comunicación presenta los resultados de varios años de trabajo con esta herramienta, las diversas experiencias de formación y evaluación de conocimientos sobre Botánica Forestal. Se han definido más de 2500 preguntas, la mayoría basadas en imágenes y realizado mas de 4300 sesiones de evaluación en la Escuela Universitaria de Ingeniería Técnica Forestal de la Universidad Politécnica de Madrid en colaboración con la Universidad de Málaga

Radiation-damage produced in BaHfO₃ irradiated with thermal and fast-neutrons

Samples of BaHfO₃ were irradiated with fast and thermal neutrons to produce ^181Hf. Attenuations of the gamma-gamma perturbed angular correlations in ^181Ta were observed, and they may have been caused by the interaction between defects (produced during or after neutron irradiation) and oxygen vacancies. Several defect structures were detected. For one of the structures, an excitation energy of 12 meV was measured, which was attributed to an electron state below the conduction band. The values of the dielectric constant and of the effective electron mass were also deduced

Efficient training of energy-based models via spin-glass control

[EN] We introduce a new family of energy-based probabilistic graphical models for efficient unsupervised learning. Its definition is motivated by the control of the spin-glass properties of the Ising model described by the weights of Boltzmann machines. We use it to learn the Bars and Stripes dataset of various sizes and the MNIST dataset, and show how they quickly achieve the performance offered by standard methods for unsupervised learning. Our results indicate that the standard initialization of Boltzmann machines with random weights equivalent to spin-glass models is an unnecessary bottleneck in the process of training. Furthermore, this new family allows for very easy access to low-energy configurations, which points to new, efficient training algorithms. The simplest variant of such algorithms approximates the negative phase of the log-likelihood gradient with no Markov chain Monte Carlo sampling costs at all, and with an accuracy sufficient to achieve good learning and generalization.ML and AA groups acknowledge the Spanish Ministry MINECO and State Research Agency AEI (FIDEUA PID2019-106901GBI00/10.13039/501100011033, Severo Ochoa Grant Nos. SEV-2015-0522 and CEX2019-000910-S, FPI), the European Social Fund, Fundacio Cellex, Fundacio Mir-Puig, Generalitat de Catalunya (AGAUR Grant Nos. 2017 SGR 1341 and SGR 1381, CERCA program, QuantumCAT U16-011424, co-funded by ERDF Operational Program of Catalonia 2014-2020), ERC AdG NOQIA and CERQUTE, EU FEDER, MINECO-EU QUANTERA MAQS (funded by the State Research Agency AEI PCI2019-111828-2/10.13039/501100011033), the National Science Centre, Poland-Symfonia Grant No. 2016/20/W/ST4/00314 and the AXA Chair in Quantum Information Science. A P-K acknowledges funding from Fundacio Obra Socialla Caixa' (LCF/BQ/ES15/10360001) and the European Union's Horizon 2020 research and innovation programme-Grant Agreement No. 648913. G M-G acknowledges funding from Fundacio Obra Social 'la Caixa' (LCF-ICFO grant). M A G-M acknowledges funding from the Spanish Ministry of Education and Vocational Training (MEFP) through the Beatriz Galindo program 2018 (BEAGAL18/00203).Pozas-Kerstjens, A.; Muñoz-Gil, G.; Piñol, E.; Garcia March, MA.; Acín, A.; Lewenstein, M.; Grzybowski, PR. (2021). Efficient training of energy-based models via spin-glass control. Machine Learning: Science and Technology. 2(2). https://doi.org/10.1088/2632-2153/abe8070250262