Complex patterns on the plane: different types of basin fractalization in a two-dimensional mapping

Basins generated by a noninvertible mapping formed by two symmetrically coupled logistic maps are studied when the only parameter \lambda of the system is modified. Complex patterns on the plane are visualised as a consequence of basins' bifurcations. According to the already established nomenclature in the literature, we present the relevant phenomenology organised in different scenarios: fractal islands disaggregation, finite disaggregation, infinitely disconnected basin, infinitely many converging sequences of lakes, countable self-similar disaggregation and sharp fractal boundary. By use of critical curves, we determine the influence of zones with different number of first rank preimages in the mechanisms of basin fractalization.Comment: 19 pages, 11 figure

Reflexiones: ¿son factibles las plataformas virtuales en la enseñanza a mayores?

Este artículo recoge un conjunto de reflexiones de cara a la posibilidad de incorporar las plataformas virtuales en la enseñanza universitaria a mayores. Para ello nos hemos basado en la experiencia en la que participamos, el AUM La Línea, en la que impartimos clases. Desde el plan de estudios de este aula, hemos analizado las posibles dificultades en contenidos y en metodologías que podíamos encontrarnos de cara a la implantación de una plataforma virtual en el AUM. También hemos querido escuchar sus opiniones entrevistando a alguno alumnos sobre preferencias de nuestros alumnos, así como de los aspectos que más valoran tras el paso por el AUM. Como conclusión general, adelantamos que las plataformas virtuales pueden ser muy válidas en los procesos de aprendizaje de los alumnos del AUM, si se plantean como un complemento a la presencialidad en las aulas.This article shows a group of thoughts about the possibilities of virtual platforms in university teaching to elderly. We have started from our experience on an Elderly University Class called “La Línea”. We have analysed the difficulties in contents and methodology we could find using virtual platforms with this students. We also wanted to hear the students opinions. So we interviewed some of them about their preferences and the aspects they give more value after studying in our school. As general conclusions, we can say that virtual platforms can be very valuable in learning process of this students if we establish them as “something else”, completing presencial classes

Performance of malolactic fermentation by inoculation of selected Lactobacillus plantarum and Oenococcus oeni strains isolated from Rioja red wines

Malolactic fermentations (MLF) of wines inoculated with selected lactic acid bacteria strains of the species Oenococcus oeni and Lactobacillus plantarum were studied and compared with spontaneous MLF. Bacterial populations were monitored along the whole process of MLF and bacteria identifications were carried out at species and strain level. Macrorestriction analysis with SfiI endonuclease and subsequent PFGE was carried out in order to identify O. oeni individual strains. L. plantarum active lyophila did not survive competing with the indigenous microbiota in a wine with 15.3 % (vol/vol) alcohol, whereas the selected O. oeni strains carried out wine MLF. The highest production of histamine took place during MLF in those wines that underwent spontaneous MLF with a mixed population of indigenous strains. The lowest levels of histamine were obtained with the selected commercial O. oeni strain that succeeded 100 % over the indigenous microbiota. Results indicate that development of MLF leaded by selected O. oeni active lyophila provides negligible histamine levels in red wines of quality that can be submitted to subsequent ageing in wood.

Influence of the Yesa reservoir on floods of the Aragón River, central Spanish Pyrenees

International audienceThe Yesa reservoir, the largest Pyrenean reservoir, was constructed in 1959 to supply water to new irrigated areas in the Ebro Depression, NE Spain. It is filled from October to May-June and then releases large quantities of water in the summer via the Bardenas Canal. The results confirm that the frequency of floods downstream of the dam decreased. The reduction mainly depends on two factors: i) the water storage level, and ii) the season of the year. Floods are very well controlled when the reservoir level is lower than 50%. Between 50 and 70%, only the highest floods are controlled. Finally, the reservoir retains mainly autumn and spring floods; most winter floods are released downstream to ensure the safety of the dam. Keywords: reservoir, flood control, flood seasonality, flood frequency, river regime, Pyrenees</p

Probabilistic models to assist maintenance of multiple instruments

The paper discusses maintenance challenges of organisations with a huge number of devices and proposes the use of probabilistic models to assist monitoring and maintenance planning. The proposal assumes connectivity of instruments to report relevant features for monitoring. Also, the existence of enough historical registers with diagnosed breakdowns is required to make probabilistic models reliable and useful for predictive maintenance strategies based on them. Regular Markov models based on estimated failure and repair rates are proposed to calculate the availability of the instruments and Dynamic Bayesian Networks are proposed to model cause-effect relationships to trigger predictive maintenance services based on the influence between observed features and previously documented diagnostic

Resposta positiva de la fauna a la millora en els contaminants bioacumulables: el cas dels peixos i de la llúdriga com a bioindicadors

Es presenten els resultats sobre els nivells de compostos bioacumulables (PCB, pesticides i metalls pesants) en els teixits de conills, peixos i depredadors (llúdriga i visons). Els nivells són menors en els organismes terrestres que en els aquàtics i han anat disminuint a la biosfera. Els animals han respost positivament, en diversos casos, estan recuperant la seva distribució antiga. Això té, a més, implicacions positives per als humans i per a una vida de més qualitat ambiental

Optimisation of energy supply at off-grid healthcare facilities using Monte Carlo simulation

In this paper, we present a methodology for the optimisation of off-grid hybrid systems (photovoltaic-diesel-battery systems). A stochastic approach is developed by means of Monte Carlo simulation to consider the uncertainties of irradiation and load. The optimisation is economic; that is, we look for a system with a lower net present cost including installation, replacement of the components, operation and maintenance, etc. The most important variable that must be estimated is the batteries lifespan, which depends on the operating conditions (charge/discharge cycles, corrosion, state of charge, etc.). Previous works used classical methods for the estimation of batteries lifespan, which can be too optimistic in many cases, obtaining a net present cost of the system much lower than in reality. In this work, we include an advanced weighted Ah-throughput model for the lead-acid batteries, which is much more realistic. The optimisation methodology presented in this paper is applied in the optimisation of the electrical supply for an off-grid hospital located in Kalonge (Democratic Republic of the Congo). At the moment, the power supply relies on a diesel generator; batteries are used in order to ensure the basic supply of energy when the generator is unavailable (night hours). The optimisation includes the possibility of adding solar photovoltaic (PV) panels to improve the supply of electrical energy. The results show that optimal design could achieve a 28% reduction in the levelised cost of energy and a 54% reduction in the diesel fuel used in the generator, thereby reducing pollution. Furthermore, we discuss possible improvements to the telecommunications of the hospital

E-Learning and Labour Market: Wage-premium Analysis

The link between ICT and the demand for high-skilled labour is due to the fact that the introduction of digital technologies alters the skill requirements of occupations in three main ways (Spitz, 2003): 1) ICT capital substitutes repetitive manual and repetitive cognitive activities, 2) ICT capital is complementary to analytic and interactive activities, and 3) ICT capital increases the requirement for computing skills. Within this framework, we have analysed the determinants of labour productivity of individuals that have taken higher education programmes online to test how occupational skill requirements and the degree of ICT adoption by the industry matches skills of online students. In order to do this, we have assumed an implicit relationship between education and ability (Griliches and Mason, 1972), recognizing that online students may acquire specific skills, such as computing skills and abilities related to ICT use. For the empirical analysis we have used a database of degree students from the UOC (Universitat Oberta de Catalunya). The results from our model based on Mincerian equations show three important facts: 1) schooling is not a significant variable to explain wage differentials; 2) experience, understood as previous productivity and production losses avoided, is the most important variable explaining improvement of wages; and 3) ICT skills have a positive and significant effect on wage levels