Épica y providencialismo en el Liber gestorum de Pere Marsili

Este trabajo desvela cómo Pere Marsili, al relatar en su versión latina del Llibre dels fets de Jaume I las dos grandes tormentas en el mar que recoge la obra catalana (la de la expedición a Mallorca en 1229 y la de la expedición a Tierra Santa en 1269), recrea ecos poéticos de autores épicos latinos como Virgilio, Ovidio o Lucano e introduce modificaciones estructurales encaminadas a subrayar el paralelismo entre ambas tormentas.This study shows that Pere Marsili, in his Latin translation of the Llibre dels fets by Jaume I, inserted epic reminiscences from Latin poets such as Vergil, Ovid or Lucan when he described the storms that, according to the Catalan work, took place during the expedition to Mallorca in 1229 and to the Holy Land in 1269. He also made some structural changes in order to emphasize the parallelism between both storms

Interculturality and Teacher Education. A Study from Pre-service Teachers’ Perspective

Due to the multicultural nature of society and the failure of some of the educational models adopted to respond to cultural diversity, there is a need to pay greater attention to teachers’ training. This study examines Teacher Education students’ beliefs about cultural diversity and their relationship with pre-service teacher training as key aspects in designing intercultural teacher training proposals and improving educational practice. This quantitative, descriptive study was carried out with 1464 participants enrolled in teacher training programs. The results show that future teachers have positive beliefs about cultural diversity in general terms, but their positions diverge when dealing with specific aspects and transferring them to professional practice. These beliefs vary depending on the year group, with students who are finishing their training process having more intercultural beliefs

Is the bulbus arteriosus of fish homologous to the mamalian intrapericardial thoracic arteries?

El resumen aparece en el Program & Abstracts of the 10th International Congress of Vertebrate Morphology, Barcelona 2013.Anatomical Record, Volume 296, Special Feature — 1: P-089.Two major findings have significantly improved our understanding of the embryology and evolution of the arterial pole of the vertebrate heart (APVH): 1) a new embryonic presumptive cardiac tissue, named second heart field (SHF), forms the myocardium of the outflow tract, and the walls of the ascending aorta (AA) and the pulmonary trunk (PT) in mammals and birds; 2) the bulbus arteriosus (BA), previously thought to be an actinopterygian apomorphy, is present in all basal Vertebrates, and probably derives from the SHF. We hypothesized that the intrapericardial portions of the AA and the PT of mammals are homologous to the BA of basal vertebrates. To test this, we performed 1) a literature review of the anatomy and embryology of the APVH; 2) novel anatomical, histomorphological, and embryological analyses of the APVH, comparing basal (Galeus atlanticus), with apical (Mus musculus and Mesocricetus auratus) vertrebrates. Evidence obtained: 1) Anatomically, BA, AA, and PT are muscular tubes into the pericardial cavity, which connect the distal myocardial outflow tracts with the aortic arch system. Coronary arteries run through or originate at these anatomical structures; 2) Histologically, BA, AA, and PT show an inner layer of endothelium covered by circumferentially oriented smooth muscle cells, collagen fibers, and lamellar elastin. The histomorphological differences between the BA and the ventral aorta parallel those between intrapericardial and extrapericardial great arteries; 3) Embryologically, BA, AA, and PT are composed of smooth muscle cells derived from the SHF. They show a similar mechanism of development: incorporation of SHF‐derived cells into the pericardial cavity, and distal‐to‐proximal differentiation into an elastogenic cell linage. In conclusion, anatomical, histological and embryological evidence supports the hypothesis that SHF is a developmental unit responsible for the formation of the APVH. The BA and the intrapericardial portions of the great arteries must be considered homologous structures.Proyecto P10-CTS-6068 (Junta de Andalucía); proyecto CGL-16417 (Ministerio de Ciencia e Innovación); Fondos FEDER

Low pO2 selectively inhibits K channel activity in chemoreceptor cells of the mammalian carotid body

The hypothesis that changes in environmental O2 tension (pO2) could affect the ionic conductances of dissociated type I cells of the carotid body was tested. Cells were subjected to whole-cell patch clamp and ionic currents were recorded in a control solution with normal pO2 (pO2 = 150 mmHg) and 3-5 min after exposure to the same solution with a lower pO2. Na and Ca currents were unaffected by lowering pO2 to 10 mmHg, however, in all cells studied (n = 42) exposure to hypoxia produced a reversible reduction of the K current. In 14 cells exposed to a pO2 of 10 mmHg peak K current amplitude decreased to 35 +/- 8% of the control value. The effect of low pO2 was independent of the internal Ca2+ concentration and was observed in the absence of internal exogenous nucleotides. Inhibition of K channel activity by hypoxia is a graded phenomenon and in the range between 70 and 120 mmHg, which includes normal pO2 values in arterial blood, it is directly correlated with pO2 levels. Low pO2 appeared to slow down the activation time course of the K current but deactivation kinetics seemed to be unaltered. Type I cells subjected to current clamp generate large Na- and Ca-dependent action potentials repetitively. Exposure to low pO2 produces a 4-10 mV increase in the action potential amplitude and a faster depolarization rate of pacemaker potentials, which leads to an increase in the firing frequency. Repolarization rate of individual action potentials is, however, unaffected, or slightly increased. The selective inhibition of K channel activity by low pO2 is a phenomenon without precedents in the literature that explains the chemoreceptive properties of type I cells. The nature of the interaction of molecular O2 with the K channel protein is unknown, however, it is argued that a hemoglobin-like O2 sensor, perhaps coupled to a G protein, could be involved

Ionic currents in dispersed chemoreceptor cells of the mammalian carotid body

Ionic currents of enzymatically dispersed type I and type II cells of the carotid body have been studied using the whole cell variant of the patch-clamp technique. Type II cells only have a tiny, slowly activating outward potassium current. By contrast, in every type I chemoreceptor cell studied we found (a) sodium, (b) calcium, and (c) potassium currents. (a) The sodium current has a fast activation time course and an activation threshold at approximately -40 mV. At all voltages inactivation follows a single exponential time course. The time constant of inactivation is 0.67 ms at 0 mV. Half steady state inactivation occurs at a membrane potential of approximately -50 mV. (b) The calcium current is almost totally abolished when most of the external calcium is replaced by magnesium. The activation threshold of this current is at approximately -40 mV and at 0 mV it reaches a peak amplitude in 6-8 ms. The calcium current inactivates very slowly and only decreases to 27% of the maximal value at the end of 300-ms pulses to 40 mV. The calcium current was about two times larger when barium ions were used as charge carriers instead of calcium ions. Barium ions also shifted 15-20 mV toward negative voltages the conductance vs. voltage curve. Deactivation kinetics of the calcium current follows a biphasic time course well fitted by the sum of two exponentials. At -80 mV the slow component has a time constant of 1.3 +/- 0.4 ms whereas the fast component, with an amplitude about 20 times larger than the slow component, has a time constant of 0.16 +/- 0.03 ms. These results suggest that type I cells have predominantly fast deactivating calcium channels. The slow component of the tails may represent the activity of a small population of slowly deactivating calcium channels, although other possibilities are considered. (c) Potassium current seems to be mainly due to the activity of voltage-dependent potassium channels, but a small percentage of calcium-activated channels may also exist. This current activates slowly, reaches a peak amplitude in 5-10 ms, and thereafter slowly inactivates. Inactivation is almost complete in 250-300 ms. The potassium current is reversibly blocked by tetraethylammonium. Under current-clamp conditions type I cells can spontaneously fire large action potentials. These results indicate that type I cells are excitable and have a variety of ionic conductances. We suggest a possible participation of these conductances in chemoreception

Elasticity and melting of vortex crystals in anisotropic superconductors: Beyond the continuum regime.

The elastic moduli of vortex crystals in anisotropic superconductors are frequently involved in the investigation of their phase diagram and transport properties. We provide a detailed analysis of the harmonic eigenvalues (normal modes) of the vortex lattice for general values of the magnetic field strength, going beyond the elastic continuum regime. The detailed behavior of these wave-vector-dependent eigenvalues within the Brillouin zone (BZ), is compared with several frequently used approximations that we also recalculate. Throughout the BZ, transverse modes are less costly than their longitudinal counterparts, and there is an angular dependence which becomes more marked close to the zone boundary. Based on these results, we propose an analytic correction to the nonlocal continuum formulas which fits quite well the numerical behavior of the eigenvalues in the London regime. We use this approximate expression to calculate thermal fluctuations and the full melting line (according to Lindeman's criterion) for various values of the anisotropy parameter

Evaluación de la enseñanza con TIC

Las posibilidades que ofrecen las TIC para el desarrollo de una enseñanza flexible son diversas, pero el desarrollo de sus aplicaciones en los distintos componentes de proceso de enseñanza no ha avanzado por igual. En este sentido, actualmente se puede hablar de una escasa tradición en el uso de las TIC para la evaluación de los procesos de enseñanza. Las aplicaciones más frecuentes se relacionan con el diseño y aplicación de exámenes (fundamentalmente pruebas objetivas) o con la evaluación del proceso de aprendizaje diseñado exclusivamente con las TIC (cursos informatizados con un sistema de evaluación propio). Las TIC, por sus rasgos definitorios, ofrecen posibilidades para diseñar múltiples instrumentos; organizar la información recogida en el proceso evaluador e interpretarla, facilitando así la comprensión del proceso de aprendizaje. En este trabajo planteamos algunas posibilidades que ofrecen la TIC en el campo de la evaluación.The possibilities that ICT offer for the development of a flexible teaching are diverse, but the development of their applications in the different components of teaching process has not advanced equally. In this sense, at the moment one can speak of a scarce tradition in the use of the ICT for the evaluation of the teaching processes. The most frequent applications are related with the design and application of exams (fundamentally objective tests) or with the evaluation of the learning process designed exclusively with the ICT (courses computerized with an own evaluation system). The ICT offer possibilities to design multiple instruments; to organize the information picked up in the process appraiser and to interpret it, facilitating this way the understanding of the learning process. In this work we outline some possibilities that ICT offer in the field of the evaluation