Influence of temperature and time on the Eu3+ reaction with synthetic Na-Mica-n (n = 2 and 4)

Bentonite is accepted as the best clay material for the engineered barrier of Deep Geological Repositories (DGRs). The performance of clay as the main component of the engineered barrier in the DGR has been intensively studied and the structure of the selected clay mineral play a crucial role. In this sense, a new family of synthetic swelling silicates, Na-Mica-n, with tuned layer charge (n) values between 2.0 and 4.0 per unit cell has recently been synthesized and a general synthetic method has been reported. These swelling high-charge micas could be highly valuable for the decontamination of harmful cations. The ability of these micas to immobilize Eu3+ under subcritical conditions has been probed. The adsorption was in both non-specific sites (cation exchange mechanism) and specific sites (chemical reaction or surface defects adsorption). Moreover, its adsorption capacity, under the same conditions is higher than in saponite and far superior to the bentonites.Junta de Andalucía P12-FQM-567European Union 29178

Productivity and Collaboration Networks in the Main Spanish Sociology Journals: A Gender-Based Analysis of the Period 2001-2020

La presente investigación tiene como objetivo aplicar la perspectiva de género al estudio de la productividad y la colaboración científica en las principales revistas españolas de sociología. Para ello se ha analizado, mediante técnicas propias de la bibliometría y el análisis de redes sociales, la autoría de 3171 documentos publicados en dichas revistas durante el período 2001-2020. Partiendo de un abrumador predominio masculino, los resultados muestran una tendencia constante hacia la paridad, aunque esta solo se alcanza durante el lustro 2016-2020, y no en todos los indicadores. En conclusión, los avances en materia de género en la sociología española son todavía parciales, si bien no cabe responsabilizar de ello al sistema de vigilancia de la ciencia.The aim of this piece of research is to study productivity and scientific collaboration in the main Spanish sociology journals from a gender perspective. The authorship of 3171 documents published in these journals during the period 2001-2020 was analysed using bibliometric and social network analysis techniques. While there was an overwhelming male dominance at the start of the period, the results show a steady trend towards parity; however, this was only achieved during the 2016-2020 period, and not in all indicators. In conclusion, gender advances in sociology research have only partially come to fruition in Spain, but the scholarly monitoring system cannot be held accountable for this

¿Por qué faltan a clase los alumnos?

Como profesores, con frecuencia hemos observado que no todos los estudiantes asisten regularmente a clase y que, en momentos puntuales del curso, una cantidad significativa de ellos desaparece de las aulas. La mayoría de centros y/o profesores no disponen de instrumentos que permitan medir de forma efectiva el grado de absentismo estudiantil. Conocer los motivos de este absentismo es aún más difícil, dado que sería preciso preguntar a los estudiantes y es imposible hacerlo precisamente porque no asisten a clase. En este artículo tratamos de responder a la pregunta “¿Por qué faltan a clase los alumnos?”. Los resultados presentados se basan en una encuesta que se ha llevado a cabo durante tres semestres consecutivos. La encuesta se ha realizado en una asignatura en la que cada sesión de las prácticas de laboratorio cuenta para la nota final. Este hecho hace que, pese a que algunos alumnos dejan de asistir a las clases de teoría y/o de problemas, prácticamente nunca faltan a las de laboratorio, por lo que hemos aprovechado la última sesión de laboratorio del curso para realizar la encuesta. Además de conocer los motivos por los que faltan a clase, con el objeto de estudiar si los motivos son diferentes en función del grado de absentismo se ha clasificado a los estudiantes en 4 grupos en función del porcentaje de clases a las que han asistido. Los resultados muestran que los motivos para faltar a clase de los estudiantes que asisten con regularidad son distintos de aquellos que faltan habitualmente.Peer ReviewedPostprint (published version

Aprenentatge actiu basat en problemes

Durant anys, els autors del present treball hem practicat diversos mètodes per fomentar l'aprenentatge actiu dels estudiants a partir de la resolució de problemes, tant a la classe com fora. Els últims quatre cursos hem utilitzat a la classe de problemes de l'assignatura una metodologia que consisteix a encarregar als estudiants cada setmana que resolguin un petit conjunt de problemes que treballaran a la classe la setmana següent. A l’aula, els ajuntem en equips de tres o quatre persones, que discuteixen les respectives solucions i entreguen una solució de consens al final de la classe. Aquesta solució se'ls torna corregida en la classe següent. Els resultats recopilats durant aquests quatre cursos proven que assistir i participar activament a la classe ajuda molt en l'aprenentatge, i que treballar i pensar els problemes abans d'anar-hi, ajuda encara més, ja que permet aprofitar millor les classes. En aquests quatre anys, el 78 % dels estudiants que van realitzar almenys el 90 % dels problemes van aprovar l'assignatura mitjançant controls, sense necessitat de realitzar l'examen final, mentre que el 64 % dels estudiants que van realitzar menys del 50 % dels problemes no van aconseguir superar l'assignatura.Peer Reviewe

El Impacto de eliminar el examen final

Desde hace algún tiempo se publican en JENUI artículos donde se argumenta sobre la conveniencia de eliminar el examen final como forma de fomentar el trabajo del estudiante durante todo el curso. Convencidos de lo apropiado de la medida, los autores de este trabajo hemos decidido eliminar el examen final de la asignatura que compartimos. La asignatura se podía aprobar por evaluación continua, pero los estudiantes que no aprobaban tenían una segunda oportunidad de aprobar mediante un examen final. Hemos constatado que la posibilidad de asistir al examen final hacía que algunos estudiantes desistiesen de trabajar regularmente en el último tramo del curso. Según nuestros datos, antes de eliminar el examen final el 51,7% de los estudiantes aprobaba por evaluación continua y después del examen final el porcentaje de aprobados ha ascendido al 72,8%. Cuando hace dos años decidimos eliminar el examen final, nos debatíamos entre el miedo a quedarnos con el 51,7% de aprobados por evaluación continua y la esperanza de que los resultados de trabajar de forma continua durante todo el curso compensasen, al menos en parte, el porcentaje de estudiantes que aprobaban gracias al examen final. Los resultados académicos obtenidos desde entonces superan nuestras expectativas y muestran que no sólo la tasa de aprobados ha mejorado, sino que parece que los estudiantes aprenden mejor.Several papers have been published in JENUI in recent years about the convenience of removing the final examination as a way to promote student’s work along all the course. We are convinced about the appropriateness of the measure, so we have decided to remove the final exam in the subject we teach. Students may pass the course by continuous assessment, but students who failed had a second chance to pass through a final exam. We have found that the possibility to attend this final exam caused some students to desist of working regularly in the last stretch of the course. According to our data, before removing the final exam 51.7% of students passed by continuous assessment, and after the final exam pass rate ascended to 72.8%. When two years ago we decided to remove the final exam, we debated between the fear to stay with 51.7% pass rate by continuous assessment and the hope that the fact of being forced to work throughout the course would compensate, at least in part, the percentage of students who passed thanks to the final exam. Academic results since then exceed our expectations and show that not only the pass rate has improved, but also it looks like students learn better

Aprendizaje activo basado en problemas

Durante años, los autores del presente trabajo hemos practicado diversos métodos para fomentar el aprendizaje activo de los estudiantes a partir de la resolución de problemas, tanto en clase como fuera de ella. Los últimos cuatro cursos hemos utilizado en clase de problemas de la asignatura una metodología que consiste en encargar a los estudiantes cada semana que resuelvan un pequeño conjunto de problemas que trabajarán en clase la semana siguiente. En clase, los juntamos en equipos de tres o cuatro personas, que discuten sus respectivas soluciones y entregan una solución de consenso al final de la clase. Esta solución se les devuelve corregida en la siguiente clase. Los resultados recopilados durante estos cuatro cursos prueban que asistir y participar activamente en clase ayuda mucho en el aprendizaje, y que trabajar y pensar los problemas antes de ir, ayuda aún más, ya que permite aprovechar mejor las clases. En estos cuatro años, el 78% de los estudiantes que realizaron al menos el 90% de los problemas aprobaron la asignatura por controles, sin necesidad de realizar el examen final, mientras que el 64% de los estudiantes que realizaron menos del 50% de los problemas no consiguieron superar la asignatura.SUMMARY -- For years, the authors of this work have tried several approaches to promote active learning among our students by means of problem solving, both as homework and in class. During the last four courses we have used in our practice classes a methodology based on assigning, each week, the students a few problems to solve at home. Those same problems are later worked by the students in class, in groups of 3 or 4 persons that discuss their particular solutions and deliver a single consensus solution to the professor. The professor returns this group solution properly corrected in next theory class. The results collected during these four courses show that attending and actively participating in class helps significantly in the learning process and that working and thinking the problems at home in advance helps even more since the students take better advantage of the classes. For instance, 78% percent of the students that prepared at least 90% of the problems assigned passed the course by continuous evaluation without requiring a final exam, while 64% of the students that prepared less than 50% of the problems assigned failed to pass the course

Cultural differences in neuropsychological tests and intelligence of Cuban preschool children

The objective of this research was to determine the cultural differences in the execution of neuropsychological tests between a group of preschoolers with typical development in the province of Cienfuegos and another one in Sancti Spíritus, both in Cuba; as well as to identify the neuropsychological functions that influence intellectual performance. Sixty-seven children were selected and subdivided into groups. The Raven's Progressive Matrices Intelligence Test and the Luria Initial Neuropsychological Battery were used as neuropsychological evaluation instruments. The results showed significant differences in intelligence and various neuropsychological functions between the provinces. The neuropsychological variables influencing intellectual performance varied depending on the cultural groups. Taken together, the results suggest that cultural differences demand diverse patterns of cognitive skills that uniquely influence the development of intelligence and neuropsychological factors in preschool childhood.La investigación tuvo como objetivo determinar las diferencias culturales en la ejecución de los tests neuropsicológicos entre un grupo de preescolares con desarrollo típico de la provincia de Cienfuegos, y otro de Sancti Spíritus, ambas de Cuba; así como identificar las funciones neuropsicológicas que influyen en el rendimiento intelectual. Fueron seleccionados y subdivididos en grupos 67 niños. Como instrumentos de evaluación neuropsicológica se aplicaron la prueba de inteligencia matrices progresivas de Raven y la batería neuropsicológica Luria Inicial. Los resultados mostraron diferencias significativas en la inteligencia y diversas funciones neuropsicológicas entre las provincias. Las variables neuropsicológicas que influyen en el rendimiento intelectual, varían en dependencia de los grupos culturales. En conjunto, los resultados sugieren que las diferencias culturales demandan diversos patrones de habilidades cognitivas que influyen de forma singular en el desarrollo de la inteligencia y en los factores neuropsicológicos en la infancia preescolar

Metamorphic gradient modification in the Early Cretaceous Northern Andes subduction zone: A record from thermally overprinted high-pressure rocks

New field observations and petrological data from Early Cretaceous metamorphic rocks in the Central Cordillera of the Colombian Andes allowed the recognition of thermally overprinted high-pressure rocks derived from oceanic crust protoliths. The obtained metamorphic path suggests that the rocks evolved from blueschist to eclogite facies towards upper amphibolite to high-pressure granulite facies transitional conditions. Eclogite facies conditions, better recorded in mafic protoliths, are revealed by relic lawsonite and phengite, bleb- to worm-like diopside-albite symplectites, as well as garnet core composition. Upper amphibolite to high pressure granulite facies overprinting is supported by coarse-grained brown-colored Ti-rich amphibole, augite, and oligoclase recrystallization, as well as the record of partial melting leucosomes. Phase equilibria and pressure-temperature (P-T) path modeling suggest initial high-pressure metamorphic conditions M1 yielding 18.2–24.5 kbar and 465–580 °C, followed by upper amphibolite to high pressure granulite facies overprinting stage M2 yielding 6.5–14.2 kbar and 580–720 °C. Retrograde conditions M3 obtained through chlorite thermometry yield temperatures ranging around 286–400 °C at pressures below 6.5–11 kbar. The obtained clockwise P-T path, the garnet zonation pattern revealing a decrease in Xgrs/Xprp related to Mg# increment from core to rim, the presence of partial melting veins, as well as regional constraints, document the modification of the thermal structure of the active subduction zone in Northern Andes during the Early Cretaceous. Such increment of the metamorphic gradient within the subduction interface is associated with slab roll-back geodynamics where hot mantle inflow was triggered. This scenario is also argued by the reported trench-ward magmatic arc migration and multiple extensional basin formation during this period. The presented example constitutes the first report of Cretaceous roll-back-related metamorphism in the Caribbean and Andean realms, representing an additional piece of evidence for a margin-scale extensional event that modified the northwestern border of South America during the Early Cretaceous.The National University of Colombia is acknowledged for its financial support, providing execution of the Hermes 30362 project and a travel grant to D. S. Avellaneda-Jiménez for analytical data acquisition at the University of Arizona (Tucson, Arizona)

The Role of the Environment in Tissue P Systems with Cell Division

Classical tissue P systems with cell division have a special alphabet whose elements appear at the initial configuration of the system in an arbitrary large number of copies. These objects are shared in a distinguished place of the system, called the environment. Besides, the ability of these computing devices to have infinite copies of some objects has been widely exploited in the design of efficient solutions to computationally hard problems. This paper deals with computational aspects of tissue P systems with cell division where there is not an environment having the property mentioned above. Specifically, we establish the relationships between the polynomial complexity class associated with tissue P systems with cell division and with or without environment. As a consequence, we prove that it is not necessary to have infinite copies of some objects at the initial configuration in order to solve NP–complete problems in an efficient way.Ministerio de Ciencia e Innovación TIN2009-13192Junta de Andalucía P08 – TIC 0420

A polynomial alternative to unbounded environment for tissue P systems with cell division

The standard definition of tissue P systems includes a special alphabet whose elements are assumed to appear in the initial configuration of the system in an arbitrarily large number of copies. These objects reside in a distinguished place of the system, called the environment. Such potentially infinite supply of objects seems an unfair tool when designing efficient solutions to computationally hard problems in the framework of membrane computing, by performing a space–time trade-off. This paper deals with computational aspects of tissue P systems with cell division where there is no environment having the property mentioned above. Specifically, we prove that the polynomial complexity classes associated with tissue P systems with cell division and with or without environment are actually identical. As a consequence, we conclude that it is not necessary to have infinitely many copies of some objects in the initial configuration in order to solve NP–complete problems in an efficient way.Ministerio de Ciencia e Innovación TIN2009–13192Junta de Andalucía P08-TIC-0420