Selección óptima bajo criterios múltiples de materiales refractarios y aislantes para cazuelas metalúrgicas

ResumenHasta el presente, el problema de la selección de materiales refractarios y aislantes no se ha tratado, en toda su complejidad, como una tarea de optimización bajo criterios múltiples, sino básicamente como un problema de carácter metalúrgico. En este artículo, se expone el modelado matemático de la tarea de selección óptima bajo criterios múltiples y se analiza su complejidad matemática, considerando las dimensiones de los materiales por capas y por zonas, y la interacción entre zonas. La complejidad de la tarea formulada requiere su descomposición en tareas más sencillas, por zonas de la cazuela. Se realiza la validación experimental de los resultados numéricos obtenidos, con lo cual se evidencia la eficiencia y la calidad que se obtienen con los procedimientos utilizados. Estos procedimientos se derivan de la aplicación del método de integración de variables. En particular, se utiliza el operador de búsqueda aleatoria del extremo de una función de un código variable aplicado al problema estudiado.SummaryUntil the present the problem of the refractory and isolating materials selection has not been treated, in all its complexity, as an optimization under multiple criteria task, but basically as a metallurgical problem. In the present article the mathematical modelling of the optimal under multiple criteria task, the analysis of it mathematical complexity, considering the dimensions of the materials by layers and by zones are exposed. The complexity of the formulated task conditions the necessity of its decomposition in simpler tasks by zones of the ladle. The experimental validation of the obtained numeric results, where the efficiency and resulting quality of the used procedures is evidenced. The procedures applied are a part of the Integration of Variables method. Particularly, the Random Search of the Extremes of a Function of a Variable Code operator is applied to the problem studied

False failure in flexural fatigue tests

Flexural fatigue tests are typically run under displacement or in a straincontrolled mode. In these tests, either the oscillatory displacement amplitude or strain amplitude applied to the bottom of the specimen is kept constant. The evolution of loading required to cause fatigue is then measured. Load amplitude decreases with the number of cycles, and the specimen is considered to have failed when the load is half its initial value. This failure criterion may be erroneous when non-fragile fracture mixtures prepared with high bitumen contents or modified binders are tested. In these cases, mixtures exhibit a visco-plastic behaviour and increasingly less stress is necessary to cause strain without cracking. Mixtures are hardly deteriorated when the fatigue failure is determined, and may be subjected to a larger number of load repetitions. It is then recommended to control the evolution of loading more effectively and regard as valid only tests where load decreases sharply to very low levels, making sure that the three stages in the fatigue process have occurred.Peer ReviewedPostprint (author’s final draft

Genome-environment Interaction in type 2 Diabetes Mellitus

Introduction: type 2 diabetes mellitus is the predominant form of diabetes worldwide. It is a heterogeneous syndrome of multifactorial etiology that combines genetic and environmental factors and it is increasingly important due to its morbidity, mortality and disabling effects, which affect the quality of life of those who suffer from it and of their relatives, and due to the use of medical services. Objective: to identify the contribution of the genome-environment interaction in the genesis of type 2 diabetes mellitus in patients of the Puentes Grandes Polyclinic. Methods: an analytical study of population-based case-control was conducted from February 2015 to March 2016 at the Puentes Grandes Polyclinic. Information was obtained from a written questionnaire and the review of individual medical records. We conducted a study that included 60 cases and 120 controls. Results: the existence of familial aggregation in type 2 diabetes mellitus was confirmed, the risk of suffering the disease was 3.6 times higher when a first degree relative was affected and 3.02 times higher when the risk factor of obesity was present and the risk of becoming ill was 14.12 times higher when genetic and environmental factors were overlapped. Conclusions: Type 2 diabetes mellitus is more likely to appear when genetic and environmental factors coincide because it is a multifactorial disease in which the presence of genetic factors is not enough, but the action of a predisposing environment is required to appear.Introducción: la diabetes mellitus tipo 2 presenta una alta prevalencia a nivel mundial. Es un síndrome heterogéneo de etiología multifactorial que combina factores genéticos y ambientales y que cada vez cobra mayor importancia por su morbilidad, su mortalidad y sus efectos incapacitantes, que afectan la calidad de vida de quienes la padecen y de sus familiares, y por el uso de los servicios médicos. Objetivo: identificar la contribución de la interacción genoma-ambiente en la génesis de la diabetes mellitus tipo 2 en pacientes del Policlínico Puentes Grandes. Métodos: se realizó un estudio analítico de casos y controles con base poblacional desde febrero de 2015 a marzo de 2016 en el Policlínico Puentes Grandes. La información se obtuvo por un cuestionario escrito y la revisión de historias clínicas individuales. Se estudiaron 60 casos y 120 controles. Resultados: se constató la presencia de agregación familiar en la diabetes mellitus tipo 2, el riesgo de padecer la enfermedad fue 3,6 veces mayor cuando se tiene un familiar de primer grado afectado y 3,02 veces mayor cuando estuvo presente el factor de riesgo obesidad y el riesgo de enfermar cuando se imbricaban los factores genéticos y ambientales fue 14,12 veces mayor. Conclusiones: existe mayor probabilidad de presentar diabetes mellitus tipo 2 cuando coinciden los factores genéticos y ambientales porque es una enfermedad multifactorial en la que no es suficiente la presencia de factores genéticos, sino que se necesita la acción de un ambiente predisponente para expresarla

Transcriptome analyses throughout chili pepper fruit development reveal novel insights into the domestication process

Chili pepper (Capsicum spp.) is an important crop, as well as a model for fruit development studies and domestication. Here, we performed a time-course experiment to estimate standardized gene expression profiles with respect to fruit development for six domesticated and four wild chili pepper ancestors. We sampled the transcriptomes every 10 days from flowering to fruit maturity, and found that the mean standardized expression profiles for domesticated and wild accessions significantly differed. The mean standardized expression was higher and peaked earlier for domesticated vs. wild genotypes, particularly for genes involved in the cell cycle that ultimately control fruit size. We postulate that these gene expression changes are driven by selection pressures during domestication and show a robust network of cell cycle genes with a time shift in expression, which explains some of the differences between domesticated and wild phenotypes

Trends in Metal Oxide Stability for Nanorods, Nanotubes, and Surfaces

The formation energies of nanostructures play an important role in determining their properties, including the catalytic activity. For the case of 15 different rutile and 8 different perovskite metal oxides, we find that the density functional theory (DFT) calculated formation energies of (2,2) nanorods, (3,3) nanotubes, and the (110) and (100) surfaces may be described semi-quantitatively by the fraction of metal--oxygen bonds broken and the bonding band centers in the bulk metal oxide

VAMOS: a Pathfinder for the HAWC Gamma-Ray Observatory

VAMOS was a prototype detector built in 2011 at an altitude of 4100m a.s.l. in the state of Puebla, Mexico. The aim of VAMOS was to finalize the design, construction techniques and data acquisition system of the HAWC observatory. HAWC is an air-shower array currently under construction at the same site of VAMOS with the purpose to study the TeV sky. The VAMOS setup included six water Cherenkov detectors and two different data acquisition systems. It was in operation between October 2011 and May 2012 with an average live time of 30%. Besides the scientific verification purposes, the eight months of data were used to obtain the results presented in this paper: the detector response to the Forbush decrease of March 2012, and the analysis of possible emission, at energies above 30 GeV, for long gamma-ray bursts GRB111016B and GRB120328B.Comment: Accepted for pubblication in Astroparticle Physics Journal (20 pages, 10 figures). Corresponding authors: A.Marinelli and D.Zaboro

Palynological evidence for environmental and climatic change in the lower Guadiana valley, Portugal, during the last 13 000 years

Pollen analysis of a 48 m AMS radiocarbon-dated sediment sequence from the Guadiana estuary provides the first record of Lateglacial and Holocene vegetation history in the Algarve province of Portugal. This paper focuses on the record of terrestrial pollen taxa, which document a series of forest expansions and declines during the period 13 000 cal. BP to 1600 cal. BP and provide insights into climate evolution in southwestern Iberia. The main vegetation phases identified in the Guadiana valley are (1) Lateglacial interstadial (Allerød) forest with Quercus and Pinus under a temperate, moist, continental climate; (2) a Younger Dryas forest decline (Quercus) and expansion of pinewoods, xeric scrub and open ground habitats (with Juniperus, Artemisia, Ephedra distachya type, Centaurea scabiosa type) under arid and cold conditions; (3) an early Holocene forest/scrub/open-ground vegetation mosaic developing under a warm, dry and continental climate; (4) a maximum of Quercus forest and thermomediterranean evergreen taxa (Olea, Phillyrea, Pistacia) reflecting a warm, moist oceanic climate between c. 9000 cal. BP and c. 5000 cal. BP; and (5) the expansion of shrublands with Cistaceae and Ericaceae under a drier climatic regime and increasing anthropogenic activity since c. 5000 cal. BP. Holocene episodes of maximum climatic aridity are identified in the record of xerophytic taxa (Juniperus, Artemisia, Ephedra distachya type) centred around 10 200 cal. BP, 7800 cal. BP, 4800 cal. BP, 3100 cal. BP and 1700 cal. BP. Regional comparisons suggest a correlation of arid phases across southern Iberia and northwest Africa, which can be related to abrupt North Atlantic coolings (Bond events).Research Council studentship for WJF (NERC/S/A/2001/06109), with the support of Trinity College and the Department of Geography, University of Cambridg