On frames for Krein spaces

A definition of frames for Krein spaces is proposed, which extends the notion of ℐ-orthonormal bases of Krein spaces. A ℐ-frame for a Krein space (ℋ,[,]) is in particular a frame for ℋ in the Hilbert space sense. But it is also compatible with the indefinite inner product [ , ], meaning that it determines a pair of maximal uniformly ℐ-definite subspaces, an analogue to the maximal dual pair associated to a ℐ-orthonormal basis. Also, each ℐ-frame induces an indefinite reconstruction formula for the vectors in ℋ, which resembles the one given by a ℐ-orthonormal basis.Facultad de Ciencias Exacta

Abstract splines in Krein spaces

"Vegeu el resum a l'inici del document del fitxer adjunt"

A ferric guest inside a spin crossover ferrous helicate

A designed dimetallic Fe(II) helicate made with biphenylenebridged bispyrazolylpyridine ligands and exhibiting a process of spin crossover at temperatures above ambient is shown to encapsulate an S = 5/2 tris-oxalato Fe(III) ion. The spin relaxation dynamics of this guest are strongly reduced upon encapsulatio

Evaluación del grado de queratinización y el recuento de AgNORs en citología exfoliativa de mucosa oral normal de individuos fumadores y no fumadores

Objetivos. En individuos fumadores con mucosa oral clínicamente sana, se han observado cambios citológicos como una mayor queratinización, existiendo también reportes de un mayor grado de actividad nucleolar. En estos estudios, las células para frotis se han obtenido por medio de espátula de madera. Nuestro objetivo es evaluar la profundidad de muestras citológicas de mucosa oral obtenidas con cepillo para frotis (endobrush) y comparar el grado de queratinización y la actividad nucleolar en pacientes fumadores y no fumadores. Diseño del estudio. Se obtuvieron frotis de mucosa oral de borde de lengua clínicamente normal de 30 individuos fumadores y 30 no fumadores, utilizando espátula de madera y endobrush. Las muestras fueron teñidas con Papanicolaou y con la tinción AgNORs. Resultados. Con la espátula de madera se obtuvo un mayor porcentaje de células epiteliales superficiales anucleadas (P= 0.016) y con el endobrush se obtuvieron células más profundas (tipo intermedias) (P= 0.035). Los individuos fumadores presentaron un mayor porcentaje de células superficiales anucleadas con ambas técnicas, diferencia que fue estadísticamente significativa con la técnica endobrush (P=0.005). El promedio de AgNORs en las células nucleadas fue mayor en los individuos fumadores (3.83) que en los no fumadores (2.79) (P= 0.003). Conclusiones. El endobrush permite obtener células de estratos más profundos. Los individuos fumadores con mucosa clínicamente normal presentan un mayor porcentaje de células queratinizadas y una mayor actividad nucleolar, sugiriendo que el consumo de cigarrillo influye en la actividad celular de la mucosa del borde de lengua.Objetive.In smokers with clinically normal buccal mucosa, cytological changes such as increased keratinization, and higher nucleolar activity have been observed. In these studies the cells for cytological smears were obtained with a wooden spatula. Our objectives were to evaluate the depth of cytological smears of oral mucosa obtained with both a brush (endobrush) and a wooden spatula, and to compare the degree of keratinization and the nucleolar activity in smokers and non-smokers. Design. We obtained cytological smears of clinically normal lateral tongues of 30 smokers and 30 non-smokers using both a wooden spatula and endobrush. The samples were dyed with Papanicolaou and the AgNORs. Results. With the wooden spatula we found a greater percentage of enucleated superficial epithelial cells (P = 0.016) and deeper cells were obtained with an endobrush (intermediate cells) (P =0.035). The smokers showed a greater percentage of enucleated superficial cells with both techniques, however this difference was significantly greater with Endobrush (P=0.005). The average of AgNORs in the nucleated cells was greater in smokers (3.83) than in non-smokers (2.79) (P=0.003). Conclusion. The Endobrush allows the clinician to obtain deeper cells of buccal mucosa. Smokers with clinically normal mucosa show a greater percentage of keratinized cells and a greater nucleolar activity, suggesting that cigarette smoking influences the cellular activity of the mucosa of the lateral tongue

InstanceCollage: a tool for the particularization of collaborative IMS-LD scripts

Current research work in e-learning and more specifically in the field of CSCL (Computer Supported Collaborative Learning) deals with design of collaborative activities, according to computer-interpretable specifications, such as IMS Learning Design, and their posterior enactment using LMSs (Learning Management Systems). A script that describes such collaborative activities is typically designed beforehand in order to structure collaboration, and defines the features that determine the behavior of the LMS, for instance, the sequence of activities or the groups/role distribution. In CSCL settings, group management and composition are especially relevant and affect the chances of achieving the expected learning outcomes. This paper presents a software tool, named InstanceCollage, which aims at facilitating the configuration and population of groups for IMS-LD scripts created with the authoring tool Collage, and discusses the implications of the IMS-LD specification with respect to this task. InstanceCollage is designed to process collaboration scripts based on CLFPs (Collaborative Learning Flow Patterns). Using this type of patterns, InstanceCollage focuses on the importance of understanding the function of groups within the learning strategy of the script. This paper describes the approach taken in InstanceCollage to facilitate this understanding for non-expert users. Additionally, two case studies are presented, which represent complex authentic collaborative learning scenarios, as a proof of concept of the functionality of this tool. The case studies are also used to illustrate the requirements of group configuration tools and to show that InstanceCollage complies to such requirements

Design-aware analytics supporting teachers’ monitoring of blended learning scenarios: Two experiences in higher education

From the conceptualization to the evaluation of blended learning scenarios, teachers address multiple tasks, sometimes being overwhelmed on account of the required time and associated burden. To support teachers in this endeavor, we propose to connect the pedagogical decisions made at design time with the analysis of the participants’ interactions. In this paper, we evaluate the proposal in two authentic scenarios where we analysed whether the script-aware monitoring process provided the participant teachers with relevant information for the orchestration of blended learning scenarios. The participant teachers valued the proposal positively in terms of representativeness, novelty, relevance, required effort, and perceived usefulness. Additionally, they stated that it was helpful for the orchestration of the learning scenarios

Regímenes políticos y golpes de estado como determinantes del acceso a la electricidad

En el mundo, alrededor de 760 millones de personas siguen sin tener acceso a la electricidad, especialmente en las zonas rurales de los países en desarrollo. Aunque a lo largo de los años este hecho ha ido ganando importancia en los Objetivos de Desarrollo Sostenible y la cifra de personas sin acceso se ha ido reduciendo, se espera que para 2030 aun haya 674 millones sin acceso a la electricidad. La falta de acceso a la electricidad o la limitación a ella puede generar problemas de salud e incidir en el bienestar de las personas. Este trabajo analiza si el tipo de régimen y los golpes de estado, afectan al acceso de la electricidad. En particular, analizamos el acceso nacional, urbano y rural, para la muestra global de países y para las economías de rentas no altas, con y sin categorías de régimen. En los resultados encontramos que no existen diferencias en el acceso a la electricidad si diferenciamos un gobierno democrático del dictatorial, pero sí hallamos que una dictadura militar reduce el acceso. Además, hemos comprobado que los golpes de estado tienen incidencia sobre la variación anual del acceso a la electricidad y que, los golpes fallidos para cada unas de las categorías de régimen tienen el mismo efecto que los producidos en la democracia parlamentaria, a excepción de la democracia mixta, en la que se obtiene un efecto positivo y superior en las zonas rurales.Around 760 million people in the world still lack access to electricity, especially in rural areas of developing countries. Although over the years this fact has been gaining importance in the Sustainable Development Goals and the number of people without access has been decreasing, it is expected that by 2030 there will still be 674 million people without access to electricity. Lack of or limited access to electricity can lead to health problems and affect people's well being. This paper analyzes whether regime type and coups d'état affect electricity access. We analyze national, urban and rural access for the global sample of countries and for non-high-income economies, with and without regime categories. In the results, we find that there are no differences in access to electricity if we differentiate between a democratic and a dictatorial government, but we do find that a military dictatorship reduces access. In addition, we found that coups have an impact on the annual variation in access to electricity and that failed coups for each of the regime categories have the same effect as those produced in parliamentary democracy, with the exception of mixed democracy, where a positive and higher effect is obtained in rural areas

Speaking the Unspeakable : Subversive Eroticism in Kate Chopin's The Awakening and Edith Wharton's Summer

This research analyzes and compares the use of eroticism as a means of subversion in Kate Chopin's The Awakening and Edith Wharton's Summer. Being published in a notably repressive period, especially concerning female sexuality, these two novels, by putting their focus in their heroines' sexual awakening, transgressed the social norms of their time. Chopin and Wharton erotize their heroines in order to question the established order, which, a part from subjugating female desire, made of women completely dependent beings without intellectual aspirations. By erotizing their heroines, they empower them and provide them with both personal and sexual agency.Aquesta recerca analitza i compara l'ús de l'erotisme com a eina subversiva en The Awakening, de Kate Chopin, i Summer, d'Edith Wharton. Publicades en un període notablement repressiu, sobretot quant a la sexualitat femenina, aquestes novel·les, focalitzades en el despertar sexual de les seves protagonistes, van transgredir les normes socials de l'època. Chopin i Wharton erotitzen les seves protagonistes per tal de qüestionar l'ordre establert, el qual, a banda de subjugar el desig femení, feia de la dona un ésser completament dependent sense aspiracions intel·lectuals. Erotitzant les protagonistes, doncs, les empoderen i els hi atorguen agència, tant personal com sexual

Scripting and monitoring meet each other: Aligning learning analytics and learning design to support teachers in orchestrating CSCL situations.

From the conceptualization to the evaluation of computer-supported collaborative learning (CSCL) scenarios, teachers address multiple tasks, sometimes being overwhelmed on account of the required time and associated burden. To support teachers in this endeavor, we propose to connect the pedagogical decisions made at design time with the analysis of the participants' interactions. Thus, teachers would be provided with relevant and coarse-grained information that could help them manage their CSCL scenarios. This paper synthesizes the main contributions obtained from a 3-year design-based research process, and presents the findings obtained from the evaluation of the current proposal in two authentic CSCL scenarios. The participant teachers valued the proposal positively and stated that it was helpful for their orchestration of CSCL scenarios