Stochastic multi-scale models of competition within heterogeneous cellular populations: simulation methods and mean-field analysis

We propose a modelling framework to analyse the stochastic behaviour of heterogeneous, multi-scale cellular populations. We illustrate our methodology with a particular example in which we study a population with an oxygen-regulated proliferation rate. Our formulation is based on an age-dependent stochastic process. Cells within the population are characterised by their age. The age-dependent (oxygen-regulated) birth rate is given by a stochastic model of oxygen-dependent cell cycle progression. We then formulate an age-dependent birth-and-death process, which dictates the time evolution of the cell population. The population is under a feedback loop which controls its steady state size: cells consume oxygen which in turns fuels cell proliferation. We show that our stochastic model of cell cycle progression allows for heterogeneity within the cell population induced by stochastic effects. Such heterogeneous behaviour is reflected in variations in the proliferation rate. Within this set-up, we have established three main results. First, we have shown that the age to the G1/S transition, which essentially determines the birth rate, exhibits a remarkably simple scaling behaviour. This allows for a huge simplification of our numerical methodology. A further result is the observation that heterogeneous populations undergo an internal process of quasi-neutral competition. Finally, we investigated the effects of cell-cycle-phase dependent therapies (such as radiation therapy) on heterogeneous populations. In particular, we have studied the case in which the population contains a quiescent sub-population. Our mean-field analysis and numerical simulations confirm that, if the survival fraction of the therapy is too high, rescue of the quiescent population occurs. This gives rise to emergence of resistance to therapy since the rescued population is less sensitive to therapy

Gender diversity on Boards of Directors and business success

This paper analyzes the relationship between gender diversity on Boards of Directors and business success. For this purpose, the authors used one sample of companies listed on the Madrid Stock Exchange. The paper analyzes a period of three years, between 2005 and 2007. A descriptive analysis has been carried out. Women’s labor status has been studied in these three years. The paper also covers a panel analysis. The results show that there are few women in decision-making positions, and Gender diversity and business success are not related

Modelo de cuantificación del consumo energético en edificación

The research conducted in this paper focuses on the generation of a model for the quantification of energy consumption in building. This is to be done through one of the most relevant environmental impact indicators associated with weight per m2 of construction, as well as the energy consumption resulting from the manufacturing process of materials used in building construction. The practical application of the proposed model on different buildings typologies in Seville, will provide information regarding the building materials, the subsystems and the most relevant construction elements. Hence, we will be able to observe the impact the built surface has on the environment. The results obtained aim to reference the scientific community, providing quantitative data comparable to other types of buildings and geographical areas. Furthermore, it may also allow the analysis and the characterization of feasible solutions to reduce the environmental impact generated by the different materials, subsystems and construction elements commonly used in the different building types defined in this study.La investigación realizada en el presente trabajo plantea la generación de un modelo de cuantificación del consumo energético en edificación, a través de uno de los indicadores de impacto ambiental más relevantes asociados al peso por m2 de construcción, el consumo energético derivado del proceso de fabricación de los materiales de construcción empleados en edificación. La aplicación práctica del modelo propuesto sobre diferentes tipologías edificatorias en Sevilla aportará información respecto a los materiales de construcción, subsistemas y elementos constructivos más impactantes, permitiendo visualizar la influencia que presenta la superficie construida en cuanto al impacto ambiental generado. Los resultados obtenidos pretenden servir de referencia a la comunidad científica, aportando datos numéricos que podrán ser comparados en otras tipologías y ámbitos geográficos, a la vez que permitirán analizar y precisar mejoras en cuanto al impacto ambiental generado por los diferentes materiales, subsistemas y elementos constructivos habitualmente utilizados en las tipologías edificatorias definidas

Does Board Gender Diversity Influence Financial Performance? Evidence from Spain

In recent years, several countries have enacted guidelines and/or mandatory laws to increase the presence of women on the boards of companies. Through these regulatory interventions, the aim is to eradicate the social and labor grievances that women have traditionally experienced and which has relegated them to smaller-scale jobs. Nevertheless, and despite the advances achieved, the female representation in the boardroom remains far from the desired levels. In this context, it is now necessary to enhance the advantages of board gender diversity from both ethical and economic points of view. This article examines the relation between board gender diversity and economic results in Spain: the second country in the world to legally require gender quotas in boardrooms and historically characterized by a minimal female participation in the workforce. Based on a sample of 125 non-financial firms listed on the Madrid Stock Exchange from 2005 to 2009, our findings show that in the period analyzed the increase of the number of women on boards was over 98 %. This suggests that compulsory legislation offers an efficient framework to execute the recommendation of Spanish codes of good governance by means of the increase in the number of women in the boards of firms. Furthermore, we find that the increase in the number of women on the boards is positively related to higher economic results. Therefore, both results suggest that gender diversity in boardrooms should be incremented, mandatory laws being a key factor to do so

The development of the digital teaching competence from a sociocultural approach

En la actualidad, la competencia digital docente trasciende de la formación individual del profesorado en materia TIC. El marco europeo DigCompEdu incide en que el profesorado tiene que capacitar al alumnado en la aplicación de las tecnologías digitales de forma crítica y responsable en cuanto a información, comunicación, generación de contenido, bienestar y resolución de problemas. Pese a las buenas intenciones para sistematizar un modelo común de desarrollo de la competencia digital, se detecta que las propuestas carecen de un enfoque pedagógico que sirva de base teórica de los mismos. Este trabajo propone un modelo de desarrollo de la competencia digital docente basado en el enfoque sociocultural mediante cuatro constructos: Dominio, Preferencia, Reintegración y Apropiación. Para ello, se elaboró una escala ad hoc para registrar la competencia digital docente a través del desarrollo de esta en sus estudiantes, aportando evidencias empíricas. Se plantea un diseño de tipo cuestionario. La muestra se compone de 1.881 estudiantes de educación obligatoria de Andalucía. Para el análisis de datos se utilizó SPSS. Los resultados promedios generales por cada una de las dimensiones estudiadas revelan un nivel medio de desarrollo de la competencia digital. Se concluye que aún existe mucho por hacer en cuanto a la formación del profesorado en materia TIC, siendo necesario facilitarles estrategias para el desarrollo de esta en sus estudiantes.Abstract Many Nowadays, digital teaching competence transcends the individual training of teachers in ICT. The European framework DigCompEdu, highlights that teachers must train students in the application of digital technologies in a critical and responsible way, in terms of information, communication, content generation, wellbeing and problem solving. Despite the good intentions to systematize a common model of development of digital competence, it is detected that the proposals lack a pedagogical approach that serves as a theoretical © COMUNICAR, 61 (2019-4); e-ISSN: 1988-3293; Preprint DOI: 10.3916/C61-2019-02 framework for them. This paper proposes a development model of the digital teaching competence based on the sociocultural approach through four constructs: Command, Preference, Reintegration and Appropriation. For this study, an ad hoc scale is created to record the digital teaching competence through the development of this in their students and empirical evidences are provided. A survey type design is proposed. The sample consists of 1,881 students of compulsory education in Andalusia (Spain). SPSS is used to analyse data. The average general results for each of the dimensions studied reveal a medium level of development of digital competence. It is concluded that there is still too much to be done in terms of teacher training in ICT, being necessary to provide them strategies for the development of this in their students

II Coloquio Intemacional de Teatro en Montevideo (13-15 octubre 2006)

II Coloquio Intemacional de Teatro en Montevideo (13-15 octubre 2006