2,652 research outputs found
Modelización geoquímica de los procesos de fusión parcial
18 páginas, 6 figuras, 1 apendice.[ES] Durante la fusión, los elementos traza y los isótopos estables sufren fraccionación
mientras que los isótopos radiogénicos no varían. Como la distribución de los primeros
entre las fases que intervienen sigue las leyes de las soluciones diluidas, se pueden establecer
ecuaciones relativamente sencillas, que posibilitan la modelización del proceso. A
su vez, el comportamiento de los isótopos radiogénicos hace que los magmas hereden la
signatura del sólido del que derivar, lo que facilita la identificación del mismo.
Las ecuaciones propuestas para los diferentes tipos de fusión indican que en la fusión
en equilibrio la abundancia en el fundido de elementos traza altamente incompatibles
alcanza valores muy elevados al comienzo del proceso y disminuye progresivamente al
aumentar el grado de fusión, mientras que la concentración de los elementos compatibles
crece lentamente al aumentar el porcentaje de fusión y bruscamente cuando éste alcanza
valores muy altos. En la fusión fraccionada el primero de los líquidos que se genera
removiliza casi completamente a todos los elementos altamente incompatibles del sistema,
y los sucesivos líquidos producidos tienen muy baja concentración en dichos elementos.
En la fusión incongruente se generan líquidos ricos en aquellos elementos traza
que tienen altos coeficientes de reparto para las fases que funden y bajos para las de
nueva formación, mientras que están empobrecidos en los elementos que entran en estas
últimas fases. Si la fusión tiene lugar en presencia de una fase fluida el líquido está
empobrecido, en relación al generado cuando dicha fase está ausente, en aquellos elementos
que tienen coeficientes de reparto líquido-fluido aproximadamente iguales a la
unidad, ya que una parte de los mismos se concentra en el fluido. Finalmente, en la
fusión en desequilibrio o no difusión a la primera fracción de líquido que aparece tiene una
concentración en elementos incompatibles superior y en elementos compatibles inferior
a la del sólido del que deriva, con lo que la interfase sólido-líquido se empobrece y se
enriquece, respectivamente. Sin embargo, al final del proceso la concentración de los
elementos en el líquido se iguala a la que tenía la parte de sólido que ha fundido.
Para modelizar la fusión parcid en equilibrio se pueden seguir dos vías diferentes,
según se disponga o no de los coefcientes de reparto mineral-líquido y se conozcan o no
los porcentajes en los que intervienen dichas fases. Si se dispone de dichos parámetros,
se puede intentar duplicar las concentraciones elementales observadas en los líquidos
primarios, previa selección de unas constantes razonables. Por el contrario, si no se
conocen aquellos parámetros la mJdelización se puede llevar a cabo de forma distinta,
según se disponga de la composición de los líquidos generados o del residuo. Si se conoce
la composición de los líquidos generados, se utilizan las variaciones en las concentraciones
elementales que presentan las rocas, mediante un ajuste simultáneo de todas ellas
por resolución de un sistema de ecuaciones formado por las expresiones que describen el
proceso, para un número suficiente de elementos, o bien independientemente para cada
parámetro y elemento. A su vez, si se conoce la composición química de los residuos
hay que suponer la composición del protolito y a partir del elemento más residual fijar
los dos parámetros que quedan por conocer: el coeficiente de partición global residuofundido
para los distintos elementos y el grado de fusión que ha sufrido cada restita, asumiendo,
según proceda, el grado de fusión, el coeficiente de reparto global de uno de los
elementos o la concentración del mismo.[EN] During melting processes both stable isotopes and trace elements fractionate, whereas
radiogenic isotopes do not change. The distribution of the former between the phases
that participate, follows diluted solutions laws in such a way that it is possible to establish
relatively simple equations to model these processes. Additionally, the radiogenic
isotopes behaviour implies that the magmas retain the source signature thus allowing its
identification.
In the case of equilibrium melting, the highly incompatible elements abundance is
very high in the liquid at the beginning of the process and decreases progressively as the
melting degree increases. On the contrary, the concentration in compatible elements
grows very slowly during the first steps to increase sharply for the highest F values.
During fractional melting, the first liquid generated removes almost all the incompatible
elements thus producing a relative depletion in those elements in the successive liquids.
In the case of incongruent melting, the magmas are enriched in the trace elements with
high distribution coefficients for the phases that melt and low for the newly generated
phases, and are impoverished in the elements that constitute the new phases. If melting is
produced in the presence of a fluid phase, the liquid will be depleted in those elements
with fluid/liquid distribution coefficients close to 1, rdative to the same liquid generated
without a fluid phase. Finally, during disequilibrium or nondiffusive melting, the first
liquid fraction has a concentration in incompatible dements higher and in compatible
elements lower than that in the source, so the solid-liquid interface is depleted and enriched,
respectively. However, at the end of the process the concentration of elements in
the liquid is equated to the abundance in the solid that melted.
To model equilibrium me1ting two diferent approaches can be followed, depending
on the availability of the mineral-liquid distribution coefficients and the percentages in
which the mineral phases have participated. When these parameters are known, it is possible
to duplicate the concentrations observed in the primary liquids by selecting reasonable
constants. On the contrary, when these parameters are unknown the approach to
follow will depend on the knowledge of the cbmposition of the liquids or that of the residue.
In the first case, the element concentrations of tbe rocks are used to obtain a simultaneous
best-fit solution of a system constituted by tile equations that describe the process,
either for a number of elements, or individually for each parameter and element. If
the composition of the residue is known, it is necessary to guess the composition of the
protolith. Then, from the most residual element the two remaining parameters (the residue-
melt bulk distribution coefficient and the degree of melting of each restite) are defined,
either assuming the degree of melting, the elements bulk distribution coefficient, or
their concentration.Este trabajo se ha realizado dentro del Proyecto de Investigación
PB92-lOS «Magmatismo intraplaca relacionado con puntos
calientes en la Península Ibérica», financiado por la Dirección
General de Investigación Científica y Técnica.Peer reviewe
Calculation of the interventilatory threshold area: a method for examining the aerobic-anaerobic transition
El objetivo fue determinar la relación entre el área interumbrales (ITA) [la zona comprendida entre el primer y el segundo umbral ventilatorio (VT1 y VT2) en la función VO2/VE, Carga/VO2 y Carga/VE] y las variables ergoespirométricas. Treinta y tres hombres realizaron un test incremental. El ITA se calculó: 1) como la integral definida por el área entre VT1 y VT2 bajo las curvas de VO2/VE, Carga/VO2 y Carga/VE y 2) como la suma de las áreas descritas por el triángulo y rectángulo entre los mismos puntos. El ITA para la función Carga/VE se correlacionó positivamente (p<0,01) con la carga en VT2 (r = 0,831) y la ventilación en VT2 (r = 0,799). El ITA para la función VO2/VE fue significativamente mayor en los ciclistas que en los estudiantes. La determinación del ITA es un método simple para evaluar la transición aeróbica-anaeróbica durante las pruebas de esfuerzo incremental.The aim was to determine the relationship between the interthreshold area (ITA) [the area between the first and second ventilatory threshold (VT1 and VT2) for the function VO2/VE, load/VO2 and load/VE] and the traditional variables measured. Thirty-three men underwent an incremental test. The ITA was calculated: 1) as the integral defined by the area between VT1 and VT2 under the curves for the functions VO2/VE, load/VO2 and load/VE and 2) as the simple sum of the areas described by the triangle and rectangle between the same points. The mean ITA for the function load/VE was positively correlated (p<0.01) with load at VT2 (r=0.831) and ventilation at VT2 (r=0.799). The mean ITA for the function VO2/VE was significantly greater in the cyclists than in the students. The ITA for the function load/VE differed between March and July as training progressed. The determination of the ITA is a simple method of assessing the aerobic-anaerobic transition process during incremental exercise tests
Microwave-driven synthesis of bisphosphonate nanoparticles allows in vivo visualisation of atherosclerotic plaque
A fast and reproducible microwave-driven process has allowed us to synthesise neridronate-functionalised nanoparticles. Contrary to tradition, the phosphate groups decorate the outside layer of the particles providing Ca2+ binding properties in vitro and selective accumulation in vivo in the atheroma plaque. In vivo and ex vivo detection by T2-weighted MRI is demonstrated and validated by histology. The accumulation in the plaque takes place in less than one hour following the intravenous injection, which is particularly suitable for clinical applications
Developing a Model-Driven Reengineering Approach for Migrating PL/SQL Triggers to Java: A Practical Experience
©2019. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/
This document is the Submitted Manuscript version of a Published Work that
appeared in final form in Journal of Systems and Software, Volume 151, May 2019. To access the final edited and published work see https://doi.org/10.1016/j.jss.2019.01.068.Model-driven software engineering (MDE) techniques are not only useful in forward engineering scenarios, but can also be successfully applied to evolve existing systems. RAD (Rapid Application Development) platforms emerged in the nineties, but the success of modern software technologies motivated that a large number of enterprises tackled the migration of their RAD applications, such as Oracle Forms. Our research group has collaborated with a software company in developing a solution to migrate PL/SQL monolithic code on Forms triggers and program units to Java code separated in several tiers. Our research focused on the model-driven reengineering process applied to develop the migration tool for the conversion of PL/SQL code to Java. Legacy code is represented in form of KDM (Knowledge-Discovery Metamodel) models. In this paper, we propose a software process to implement a model-driven re-engineering. This process integrates a TDD-like approach to incrementally develop model transformations with three kinds of validations for the generated code. The implementation and validation of the re-engineering approach are explained in detail, as well as the evaluation of some issues related with the application of MDE
Low‐cost technologies in a rich ecological context: Hotel California open‐air site at Sierra de Atapuerca, Burgos, Spain
Hotel California is part of a network of open-air Neanderthal sites located in the Sierra de Atapuerca (Burgos, Spain). In this study, we examine the technology of the lithic assemblages recovered from this site's archaeological levels 3 to 7, which are characterised by the use of local raw materials, non-hierarchical centripetal exploitation systems, systematic production of flakes and few retouched items. This type of expedient technology is repeated throughout the entire sequence, which spans Marine Isotope Stages (MIS) 3 to 4. Through a comparison with the technocomplexes and occupation histories of surrounding sites – including a re-evaluation of the published chronology for the nearby site of Fuente Mudarra, which is now dated exclusively to MIS 5 – we examine whether the detected pattern is applicable to the rest of the Atapuerca Mousterian record and if this expedient behaviour has equivalents in other sites in the region. Our findings show that the lithic procurement, exploitation and configuration strategies employed at the Sierra de Atapuerca open-air sites were constant over broad time periods spanning MIS 5 to 3, in contrast to the technological sequences observed at other nearby sites on the Northern Iberian Plateau. The recurrent settlement of these open-air Neanderthal sites over tens of thousands of years and the consistent use of expedient technologies during different occupation periods is likely attributable to the rich ecological context of the Sierra de Atapuerca environs.This work was funded by the Spanish Ministry projects CGL2012-38434-C03-02, CGL2015-65387-C3-3-P and PGC2018-093925-B-C31. The field excavation work was funded by the Junta de Castilla y León and Fundación Atapuerca. Marta Santamaría has a predoctoral fellowship from the University of Burgos. Martina Demuro is supported by Australian Research Council Future Fellowship grant FT200100816. The excavation team has made this research possible. We would like to give special thanks to Hector de la Fuente and Pedro Alonso, colleagues of the Prehistory Laboratory of the UBU, for their constant support
Heart rate profile in highly trained triathletes
Nueve triatletas hombres (68,0 ± 2,0 mL·kg-1·min-1, 25 ± 1,9 años, 68,3 ± 2,2 kg y 1,77 ± 0,22 m), realizaron un test incremental en cicloergómetro en tres ocasiones correspondientes con el inicio de la temporada, periodo precompetitivo y periodo competitivo. El consumo de oxígeno máximo y los umbrales ventilatorios (aeróbico y anaeróbico respectivamente) fueron medidos en cada visita. A pesar de los cambios en la distribución del entrenamiento entre disciplinas, tiempo total de entrenamiento, tiempo de entrenamiento por semana, e intensidad del entrenamiento, potencia máxima, consumo de oxígeno máximo, frecuencia cardiaca submáxima, y concentración de lactato permanecieron estables a lo largo de la temporada. Dada la estabilidad mostrada con la relación entre la frecuencia cardiaca y los umbrales ventilatorios en nuestra muestra, concluimos que un único test de laboratorio al comienzo de la temporada podría ser suficiente para prescribir intensidades de entrenamiento (al menos en ciclismo) basándose en zonas de frecuencia cardiaca en triatletas altamente entrenados. Estos resultados deberán ser comprobados además con muestras mayores para poder ser generalizados.Nine male triathletes (68.0 ± 2.0 mL·kg-1·min-1, 25 ± 1.9 years, 68.3 ± 2.2 kg, 177.4 ± 2.2 cm), performed an incremental maximal cycle exercise test on three separate occasions corresponding to the start of the season, pre-competitive period, and competitive period. Maximal oxygen uptake and ventilatory thresholds (aerobic and anaerobic respectively) were assessed in each visit. Despite changes in the distribution of training among disciplines, total training time, training time per week, and intensity of the training, maximal power output, maximal oxygen uptake, submaximal heart rate, and lactate concentration remained stable throughout the season. Due to the stability displayed by the heart rate ventilatory thresholds relationship in our sample, we conclude that a single laboratory testing at the start of the season could be enough to prescribe training intensities (at least for cycling) based on heart rate zones in highly trained triathletes. These results should be compared in future studies with longer samples in order to be generalised.Este estudio ha sido parcialmente financiado por la Universidad Politécnica de Madrid mediante una beca de doctorado a Zapico, AG. Así como el Programa Marier Curie – COFUND (contract UNITE 246565) a becado a Díaz, V., y el Ministerio de Ciencia e Innovación a Ruiz, J. (RYC-2010-05957)
Physical activity quantification in elder women
Cuantificación de la actividad física en mujeres mayores
Altered DNA methylation in human placenta after (suspected) preterm labor
Aim: The aim of this study was to determine if alterations in DNA methylation in the human placenta would support suspected preterm labor as a pathologic insult associated with diminished placental health.
Methods: We evaluated placental DNA methylation at seven loci differentially methylated in placental pathologies using targeted bisulfite sequencing, in placentas associated with preterm labor (term birth after suspected preterm labor [n = 15] and preterm birth [n = 15]), and controls (n = 15).
Results: DNA methylation levels at the NCAM1 and PLAGL1 loci in placentas associated with preterm labor did differ significantly (p < 0.05) from controls.
Discussion: Specific alterations in methylation patterns indicative of an unfavourable placental environment are associated with preterm labor per se and not restricted to preterm birth
Geochemistry of the Quaternary alkali basalts of Garrotxa (NE Volcanic Province, Spain): a case of double enrichment of the mantle lithosphere
The area of Garrotxa (also known as the Olot area) represents the most recent (700,000–11,500 y) and better preserved area of magmatic activity in the NE Volcanic Province of Spain (NEVP). This region comprises a suite of intracontinental leucite basanites, nepheline basanites and alkali olivine basalts, which in most cases represent primary or nearly primary liquids. The geochemical characteristics of these lavas are very similar to the analogous petrologic types of other Cenozoic volcanics of Europe, which are intermediate between HIMU, DM and EM1. Quantitative trace element modeling, suggests derivation from an enriched mantle source by degrees of melting that progressively increased from the leucite basanites (,4%) to the olivine basalts (,16%). However, the relatively more variable Sr–Nd–Pb isotope signature of the magmas suggests the participation of at least two distinct components in the mantle source: (1) a sublithospheric one with a geochemical signature similar to the magmas of Calatrava (Central Spain) and other basalts of Europe; and (2) an enriched lithospheric component with a K-bearing phase present. The geochemical model proposed here involves the generation of a hybrid mantle lithosphere source produced by the infiltration of the sublithospheric liquids into enriched domains of the mantle lithosphere, shortly before the melting event that generated the Garrotxa lavas. The available geological data suggest that the first enrichment event of the mantle lithosphere under the NEVP could be the result of Late Variscan mantle upwelling triggered by the extensional collapse of the Variscan orogen during the Permo-Carboniferous. By Jurassic/Cretaceous time, large-scale NNE-directed sublithospheric mantle channeling of thermally and chemically anomalous plume material was placed under the Iberian Peninsula and Central Europe. However, the geodynamic conditions in the NEVP did not favor magmatism, which could not take place until the Cenozoic after extension started. This favored the second enrichment event of the mantle lithosphere by entrainment and storage of liquids generated in the sublithospheric plume material. After a relatively short period of time, as extension progressed, it triggered melting in the enriched portions of the mantle lithosphere during the Quaternary, generating the Garrotxa volcanism.Depto. de Mineralogía y PetrologíaFac. de Ciencias GeológicasTRUEpu
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