Modelling of heat and moisture transfer in concrete at high temperature

Moisture diffusion and related fluid pressures play a key role in cracking and spalling of concrete subject to high temperatures. This paper describes recent developments of a mode for moisture and heat transfer in porous materials, to be combined with an existing and well tested meso-mechanical model for concrete. Liquid and gas flows are formulated separately, yet later they can be combined in terms of s single variable, Pv. The material pore distribution curve is taken as the basis for developing a new physically-based desorption isotherm alternative to the traditional Bazant & Thonguthai’s model. A simple academic example for temperatures between 27 and 800ºC is presented to show the behaviour of the model

Routing design for less-than-truckload motor carriers using ant colony techniques

One of the most important challenges for Less-Than-Truck-Load carriers consists of determining how to consolidate flows of small shipments to minimize costs while maintaining a certain level of service. For any origin-destination pair, there are several strategies to consolidate flows, but the most usual ones are: peddling/collecting routes and shipping through one or more break-bulk terminals. Therefore, the target is determining a route for each origin-destination pair that minimizes the total transportation and handling cost guaranteeing a certain level of service. Exact resolution is not viable for real size problems due to the excessive computational time required. This research studies different aspects of the problem and provides a metaheuristic algorithm (based on Ant Colonies Optimization techniques) capable of solving real problems in a reasonable computational time. The viability of the approach has been proved by means of the application of the algorithm to a real Spanish case, obtaining encouraging results

Seasonal dynamic factor analysis and bootstrap inference : application to electricity market forecasting

Year-ahead forecasting of electricity prices is an important issue in the current context of electricity markets. Nevertheless, only one-day-ahead forecasting is commonly tackled up in previous published works. Moreover, methodology developed for the short-term does not work properly for long-term forecasting. In this paper we provide a seasonal extension of the Non-Stationary Dynamic Factor Analysis, to deal with the interesting problem (both from the economic and engineering point of view) of long term forecasting of electricity prices. Seasonal Dynamic Factor Analysis (SeaDFA) allows to deal with dimensionality reduction in vectors of time series, in such a way that extracts common and specific components. Furthermore, common factors are able to capture not only regular dynamics (stationary or not) but also seasonal one, by means of common factors following a multiplicative seasonal VARIMA(p,d,q)×(P,D,Q)s model. Besides, a bootstrap procedure is proposed to be able to make inference on all the parameters involved in the model. A bootstrap scheme developed for forecasting includes uncertainty due to parameter estimation, allowing to enhance the coverage of forecast confidence intervals. Concerning the innovative and challenging application provided, bootstrap procedure developed allows to calculate not only point forecasts but also forecasting intervals for electricity prices

Validity and Reliability of an Inertial Device for Measuring Dynamic Weight-Bearing Ankle Dorsiflexion

A decrease in ankle dorsiflexion causes changes in biomechanics, and different instruments have been used for ankle dorsiflexion testing under static conditions. Consequently, the industry of inertial sensors has developed easy-to-use devices, which measure dynamic ankle dorsiflexion and provide additional parameters such as velocity, acceleration, or movement deviation. Therefore, the aims of this study were to analyze the concurrent validity and test-retest reliability of an inertial device for measuring dynamic weight-bearing ankle dorsiflexion. Sixteen participants were tested using an inertial device (WIMU) and a digital inclinometer. Ankle dorsiflexion from left and right ankle repetitions was used for validity analysis, whereas test-retest reliability was analyzed by comparing measurements from the first and second days. The standard error of the measurement (SEM) between the instruments was very low for both ankle measurements (SEM 0.05) even though a significant systematic bias (~1.77°) was found for the right ankle (d = 0.79). R2 was very close to 1 in the left and right ankles (R2 = 0.85–0.89) as well as the intraclass correlation coefficient (ICC > 0.95). Test-retest reliability analysis showed that systematic bias was below 1° for both instruments, even though a systematic bias (~1.50°) with small effect size was found in the right ankle (d = 0.49) with WIMU. The ICC was very close to 1 and the coefficient of variation (CV) was lower than 4% in both instruments. Thus, WIMU is a valid and reliable inertial device for measuring dynamic weight-bearing ankle dorsiflexion

Purification of Starch Granules from Arabidopsis Leaves and Determination of Granule-Bound Starch Synthase Activity

Starch constitutes the most important carbon reserve in plants and is composed of branched amylopectin and linear amylose. The latter is synthesized exclusively by the Granule-Bound Starch Synthase (GBSS, EC 2.4.1.21). Here we report a readily reproducible, specific and highly sensitive protocol, which includes the isolation of intact starch granules from Arabidopsis thaliana leaves and the subsequent determination of GBSS activity. We have applied this method to study GBSS activity in diurnal cycles in vegetative growth and during the photoperiodic transition to flowering in Arabidopsis (Tenorio et al., 2003; Ortiz-Marchena et al., 2014).España,MINECO CSD2007-00057, BIO2008-02292, and BIO2011-28847-C02-00España, Junta de Andalucía P06-CVI-01450 and P08-AGR-0358

Preferencias educativas de los estudiantes postgraduados ante los cambios del Espacio Europeo de Educación Superior

La implantación del Espacio Europeo de Educación Superior (EEES) ha provocado profundos cambios que atañen a nuevas concepciones del proceso de enseñanza-aprendizaje. En este contexto, la técnica del Análisis Conjunto (AC) fue aplicada a una muestra de 179 postgraduados pertenecientes al Curso de Adaptación Pedagógica (CAP) 2007-2008, de la Universidad de Granada (UGR), con la intención de determinar sus preferencias hacia los cambios impuestos por el EEES. Los resultados muestran cómo las preferencias formativas de los estudiantes se centran en la adquisición de competencias para el desarrollo de habilidades, la presencialidad de las clases y un enfoque tutorial mediante seguimiento académico

Determination of Soluble Sugars in Arabidopsis thaliana Leaves by Anion Exchange Chromatography

Determination of soluble sugars is basic for the study of carbon metabolism in plants. Soluble sugar quantitation can be achieved by enzymatic methods implying different coupled reactions. Here we describe a simple method that allows rapid determination of the most abundant soluble sugars (glucose, fructose and sucrose) in Arabidopsis leaves by anion exchange chromatography. We have applied this method to study the levels of soluble sugars during the photoperiodic transition to flowering (Ortiz-Marchena et al., 2014).España, MINECO projects CSD2007-00057, BIO2008-02292, and BIO2011-28847-C02-00España, Junta de Andalucía P06-CVI-01450 and P08-AGR-0358

La dualidad historia/leyenda en Bécquer, Valle-Inclán y Antonio Machado

La mayor autoridad crítica que en general se ha concedido, en los estudios del 98, a la literatura de corte realista y presentista frente a la volcada en un pasado resueltamente mitificado corre el riesgo de minusvalorar no sólo la transcendencia social de estas últimas obras, sino también su complejidad constructiva. Este ensayo, en el cual el primer Antonio Machado es asimismo primus inter pares, quiere sustraerse a dichos peligros dando un tratamiento histórico y filosófico (apoyado en Bergson, Ortega y la “transferencia” psicoanalítica) al concepto de “leyenda” y un tratamiento poético al concepto de “historia”. En este menester comentaré en detalle un ramillete de textos en prosa y verso publicados, en su mayor parte, en la cincuentena que media entre 1857 y 1907. In studies of the Generation of 1898, realist and present-oriented literary works have been accorded greater critical authority than the literature recreating an emphatically mythic past. This gesture runs the risk of undervaluing not only the social import of the seemingly less engaged works, but also their structural complexity. My essay studies the earlier Machado in relation to Bécquer and Valle- Inclán, and seeks to avoid the pitfalls just mentioned by subjecting the poet’s concept of “leyenda” to a historical and philosophical treatment (grounded especially in Bergson, Ortega y Gasset, and the role of “transference” in psychoanalysis) while subjecting the related concept of “historia” to a poetic treatment. Most of the poems and prose pieces discussed in greater detail were published in the fifty years stretching from 1857 to 1907