Las prácticas de campo en la enseñanza de la biología y la formación docente: estado actual de conocimiento.

La presente comunicación muestra el estado actual de conocimiento sobre las prácticas de campo en la enseñanza de la Biología y en la formación de docentes de esta disciplina, a través de una revisión documental realizada sobre las publicaciones en revistas y congresos internacionales especializados en educación en ciencias naturales y enseñanza de la Biología durante los últimos 10 años. Observamos cuatro tendencias en las publicaciones: Revisiones/reflexiones, Investigaciones sobre enseñanza-aprendizaje, Investigaciones de las Concepciones sobre prácticas de campo y Relación con el Conocimiento Profesional del Profesor. En cada una de ellas mostramos sus principales características, enfoques, problemas y poblaciones de estudio. Por último señalamos la importancia de estudiar las prácticas de campo en la formación inicial del profesorado de Biología

Timed Automata Semantics for Visual e-Contracts

C-O Diagrams have been introduced as a means to have a more visual representation of electronic contracts, where it is possible to represent the obligations, permissions and prohibitions of the different signatories, as well as what are the penalties in case of not fulfillment of their obligations and prohibitions. In such diagrams we are also able to represent absolute and relative timing constraints. In this paper we present a formal semantics for C-O Diagrams based on timed automata extended with an ordering of states and edges in order to represent different deontic modalities.Comment: In Proceedings FLACOS 2011, arXiv:1109.239

Photovoltaic module segmentation and thermal analysis tool from thermal images

The growing interest in the use of clean energy has led to the construction of increasingly large photovoltaic systems. Consequently, monitoring the proper functioning of these systems has become a highly relevant issue.In this paper, automatic detection, and analysis of photovoltaic modules are proposed. To perform the analysis, a module identification step, based on a digital image processing algorithm, is first carried out. This algorithm consists of image enhancement (contrast enhancement, noise reduction, etc.), followed by segmentation of the photovoltaic module. Subsequently, a statistical analysis based on the temperature values of the segmented module is performed.Besides, a graphical user interface has been designed as a potential tool that provides relevant information of the photovoltaic modules.Comment: 7 pages, 12 Figure

Response of Saos-2 osteoblast-like cells to kilohertz-resonance excitation in porous metallic scaffolds

Post-operative therapy for joint replacement is often performed to optimize bone volume and bone-implant contact. Methods, such as pulsed therapeutic ultrasound, have been shown to be a valuable addition to regular physiotherapy to increase bone regeneration. To evaluate the efficacy of kilohertz-frequency (kHz) resonant stimuli to additively manufactured implant analogues, Saos-2 cells were seeded onto porous stainless steel scaffolds and flat substrates. Resonant frequency modes were mapped in the low kHz range, and cells were subjected to daily stimulus for 10 min at a frequency of 1.278 kHz. kHz-frequency excitation was found to increase normalized alkaline phosphatase production by almost twofold on metallic substrates relative to non-vibrated control scaffolds, while peak velocity influenced alkaline phosphatase production on porous scaffolds but not flat substrates. Total cell proliferation was downregulated by excitation, and all excited samples displayed larger variability. This work indicates that vibration within the range of 0.16–0.48 mm/s may reduce cell proliferation, but favour osteogenic gene expression. This study highlights the potential of using kHz-resonance therapy to mitigate early-onset pore occlusion to achieve uniform osseointegration through porous metallic scaffolds.Postprint (author's final draft

Hacia la prueba de corrección de clases

La actividad de desarrollar programas orientados a objetos, los cuales involucran referencias a memoria, pueden introducir errores difíciles de identificar con el uso de un razonamiento operacional. Esto da lugar a la necesidad de contar con un marco teórico para la prueba de corrección de clases. A partir de esta motivación y basándonos en la idea propuesta por B. Meyer en [Meyer 03a], trabajamos en el desarrollo de una semántica formal para probar, matemáticamente, que clases equipadas con contratos satisfacen los mismos.The activity of object oriented program development, which may involve references variables, is prone to errors which are hard to find by operational reasoning. Hence the need for a theoretical framework for proving class correctness. Given this motivation and based on ideas proposed by B. Meyer in [Meyer 03a] we develop a formal semantics for mathematically proving that contract equipped classes satisfy their specifications.Red de Universidades con Carreras en Informática (RedUNCI

In Candida parapsilosis the ATC1 gene encodes for an acid trehalase involved in trehalose hydrolysis, stress resistance and virulence

An ORF named CPAR2-208980 on contig 005809 was identified by screening a Candida parapsilosis genome data base. Its 67% identity with the acid trehalase sequence from C. albicans (ATC1) led us to designate it CpATC1. Homozygous mutants that lack acid trehalase activity were constructed by gene disruption at the two CpATC1 chromosomal alleles. Phenotypic characterization showed that atc1Δ null cells were unable to grow on exogenous trehalose as carbon source, and also displayed higher resistance to environmental challenges, such as saline exposure (1.2 M NaCl), heat shock (42°C) and both mild and severe oxidative stress (5 and 50 mM H2O2). Significant amounts of intracellular trehalose were specifically stored in response to the thermal upshift in both wild type and mutant strains. Analysis of their antioxidant activities revealed that catalase was only triggered in response to heat shock in atc1Δ cells, whereas glutathione reductase was activated upon mild oxidative stress in wild type and reintegrant strains, and in response to the whole set of stress treatments in the homozygous mutant. Furthermore, yeast cells with double CpATC1 deletion were significantly attenuated in non-mammalian infection models, suggesting that CpATC1 is required for the pathobiology of the fungus. Our results demonstrate the involvement of CpAtc1 protein in the physiological hydrolysis of external trehalose in C. parapsilosis, where it also plays a major role in stress resistance and virulence

Hacia la prueba de corrección de clases

La actividad de desarrollar programas orientados a objetos, los cuales involucran referencias a memoria, pueden introducir errores difíciles de identificar con el uso de un razonamiento operacional. Esto da lugar a la necesidad de contar con un marco teórico para la prueba de corrección de clases. A partir de esta motivación y basándonos en la idea propuesta por B. Meyer en [Meyer 03a], trabajamos en el desarrollo de una semántica formal para probar, matemáticamente, que clases equipadas con contratos satisfacen los mismos.The activity of object oriented program development, which may involve references variables, is prone to errors which are hard to find by operational reasoning. Hence the need for a theoretical framework for proving class correctness. Given this motivation and based on ideas proposed by B. Meyer in [Meyer 03a] we develop a formal semantics for mathematically proving that contract equipped classes satisfy their specifications.Red de Universidades con Carreras en Informática (RedUNCI

Distributed System Contract Monitoring

The use of behavioural contracts, to specify, regulate and verify systems, is particularly relevant to runtime monitoring of distributed systems. System distribution poses major challenges to contract monitoring, from monitoring-induced information leaks to computation load balancing, communication overheads and fault-tolerance. We present mDPi, a location-aware process calculus, for reasoning about monitoring of distributed systems. We define a family of Labelled Transition Systems for this calculus, which allow formal reasoning about different monitoring strategies at different levels of abstractions. We also illustrate the expressivity of the calculus by showing how contracts in a simple contract language can be synthesised into different mDPi monitors.Comment: In Proceedings FLACOS 2011, arXiv:1109.239

La ocupación solutrense del Abrigo de la Boja (Mula, Murcia, España)

El relleno pleistoceno del Abrigo de la Boja (ADB) empieza con un nivel adscrito al Magdaleniense superior, seguido de un potente paquete con ocupación difusa bajo el cual se desarrolla una secuencia depositada durante el último máximo glacial caracterizada por una serie de estructuras de combustión, de tipo hogar plano/amorfo (open hearth), existiendo también hogares de cubeta. Destaca un hogar enlosado, completo y muy bien conservado, excavado en 2012 y adscrito provisionalmente al Solutreogravetiense. Los niveles solutrenses subyacentes son ricos en elementos de adorno, entre los cuales conchas perforadas de Littorina obtusata y Smaragdia viridis; su industria lítica incluye raspadores, algunas puntas, y escasos buriles. La datación 14C de muestras de carbón de Juniperus sp. sitúa este paquete entre 16990 ± 70 BP (VERA-5364a), a techo, y 20980 ± 120 BP (VERA-5366), a muro. The Pleistocene fill of the La Boja rock shelter (ADB) starts with an Upper Magdalenian level, followed by a thick package with poorly defined occupations under which there is a Last Glacial Maximum sequence with combustion features, mostly of the open hearth type. A particularly well preserved and seemingly complete stone-paved hearth of probable Solutreogravettian age was excavated in 2012. The abundant ornaments in the Solutrean levels include pierced Littorina obtusata and Smaragdia viridis shells and the stone tool assem- blages feature endscrapers, some points and rare burins. The 14C dating of Juniperus sp. charcoal samples places this sequence between 16990 ± 70 BP (VERA-5364a), at the top, and 20980 ± 120 BP (VERA-5366), at the bottom

Cell dedifferentiation and epithelial to mesenchymal transitions during intestinal regeneration in H. glaberrima

<p>Abstract</p> <p>Background</p> <p>Determining the type and source of cells involved in regenerative processes has been one of the most important goals of researchers in the field of regeneration biology. We have previously used several cellular markers to characterize the cells involved in the regeneration of the intestine in the sea cucumber <it>Holothuria glaberrima</it>.</p> <p>Results</p> <p>We have now obtained a monoclonal antibody that labels the mesothelium; the outer layer of the gut wall composed of peritoneocytes and myocytes. Using this antibody we studied the role of this tissue layer in the early stages of intestinal regeneration. We have now shown that the mesothelial cells of the mesentery, specifically the muscle component, undergo dedifferentiation from very early on in the regeneration process. Cell proliferation, on the other hand, increases much later, and mainly takes place in the mesothelium or coelomic epithelium of the regenerating intestinal rudiment. Moreover, we have found that the formation of the intestinal rudiment involves a novel regenerative mechanism where epithelial cells ingress into the connective tissue and acquire mesenchymal phenotypes.</p> <p>Conclusions</p> <p>Our results strongly suggest that the dedifferentiating mesothelium provides the initial source of cells for the formation of the intestinal rudiment. At later stages, cell proliferation supplies additional cells necessary for the increase in size of the regenerate. Our data also shows that the mechanism of epithelial to mesenchymal transition provides many of the connective tissue cells found in the regenerating intestine. These results present some new and important information as to the cellular basis of organ regeneration and in particular to the process of regeneration of visceral organs.</p