Non-extensive radiobiology

The expression of survival factors for radiation damaged cells is based on probabilistic assumptions and experimentally fitted for each tumor, radiation and conditions. Here we show how the simplest of these radiobiological models can be derived from the maximum entropy principle of the classical Boltzmann-Gibbs expression. We extend this derivation using the Tsallis entropy and a cutoff hypothesis, motivated by clinical observations. A generalization of the exponential, the logarithm and the product to a non-extensive framework, provides a simple formula for the survival fraction corresponding to the application of several radiation doses on a living tissue. The obtained expression shows a remarkable agreement with the experimental data found in the literature, also providing a new interpretation of some of the parameters introduced anew. It is also shown how the presented formalism may has direct application in radiotherapy treatment optimization through the definition of the potential effect difference, simply calculated between the tumour and the surrounding tissue.Comment: 8 pages, 1 figure. Sent to MaxEnt 2010. To be submitted for publicatio

Video design adaptation to youtube advertising formats

Este trabajo en curso analiza cómo diferentes diseños publicitarios en términos de arousal (intensidad emocional) pueden contribuir a mejorar la efectividad de la video publicidad online. La literatura previa sugiere que un final con alto arousal puede incrementar la efectividad publicitaria. Para comprobar esta proposición, nuestra investigación combina diferentes metodologías: neurociencia aplicada al comportamiento del consumidor; un estudio de campo basado en una campaña publicitaria en YouTube y un estudio final. Los primeros resultados sugieren que el diseño publicitario ha de adaptarse a los nuevos formatos de video publicidad interactiva en función de los objetivos de los anunciantes.This work in progress analyzes how different arousal advertising design may enhance online video advertising effectiveness. Previous research suggests that arousing ending designs could increase ad effectiveness. To test this proposition, our research combines different methodologies: a consumer neuroscience pretest is used to identify high and low arousal sequences; a field study based on a YouTube ad campaign is used as an exploratory study which helps to determine the experimental scenarios to be used in the final study with a large sample size. Preliminary results suggest that ad design need to be adapted to new formats of interactive advertising depending on the advertisers’ goals

Econofísica: En busca de un caballo perfectamente esférico y de masa despreciable

En este artículo, se analiza a través de símiles históricos el estado de la contribución de la Física a la Economía. Para ello se hace un repaso del modo de funcionamiento de la Física, o mejor dicho, del modo de proceder de los físicos. Ésta es la principal aportación de una ciencia a la otra: una forma diferente de aproximarse a los problemas complejos a los enfrenta la economía. En la discusión planteamos, de estos problemas, los que consideramos llevan a cabo mediante sistemas informatizados, y la necesidad de, llegado al grado de complejidad que tienen tanto la economía como la ciencia económica en la actualidad, una necesaria revolución en la forma de “mirar” de los economistas. Con ello proponemos que lo que se necesita en Economía es lo que tantas veces se ha buscado (y encontrado) en física: un modelo o una serie de modelos muy sencillos que capten, de manera totalmente nueva, la “esencia” del problema. Este modelo, el caballo esférico de masa despreciable, aunque erróneo (como los anteriores), será úti

Teachers’ conceptions about the nature of technology and the Science-Technology-Society-Environment relationships

Este trabajo pretende, en primer lugar, cuestionar extendidas concepciones de la tecnología que la presentan como mera aplicación de los conocimientos científicos y que están contribuyendo a una imagen distorsionada y empobrecida de la naturaleza de la ciencia y la tecnología y, consecuentemente, al desinterés e incluso rechazo hacia su estudio. En segundo lugar se presentan los resultados de una investigación cuyo objetivo es analizar en qué medida dichas concepciones afectan incluso al profesorado encargado de la alfabetización tecnológica. Finalmente se aborda la transformación de dichas concepciones.This paper aims, firstly, to question widespread conceptions of technology, presented as a simple application of scientific knowledge, which are contributing to a distorted and impoverished view of the nature of science and technology and, therefore, to students’ lack of interest and even rejection of the study of techno-scientific subjects. Secondly, we present an analysis of how these conceptions affect even teachers in charge of technological literacy. Finally, we contemplate how to overcome these conceptions

Formas de hacer historia: entrevista a julio aróstegui

Aprovechando la visita del profesor Julio Aróstegui, conversamos con él sobre las dificultades metodológicas de ladisciplina histórica, el oficio del historiador, la forma en que se abordan los acontecimientos como objetos de estudioy el estado actual de la Historia

Imagen de la tecnología transmitida por los textos de educación tecnológica

Cuestionamos en este artículo la transmisión por los textos de tecnología de una visión simplista y socialmente neutra de la tecnología como "ciencia aplicada", ignorando, o tratando muy superficialmente, las complejas relaciones ciencia-tecnología-sociedad-ambiente (CTSA)

Concepciones docentes acerca de la naturaleza de la tecnología y de las relaciones Ciencia, Tecnología, Sociedad y Ambiente en la educación tecnológica.

This paper aims, firstly, to question widespread conceptions of technology, presented as a simple application of scientific knowledge, which are contributing to a distorted and impoverished view of the nature of science and technology and, therefore, to students' lack of interest and even rejection of the study of techno-scientific subjects. Secondly, we present an analysis of how these conceptions affect teachers in charge of technological literacy. Finally, we contemplate how to overcome these conception

Current Problems Involving the Dismantle of Asbestos- Cement Sheets in Buildings. The Case of Central Market in Alicante

The project and the works described in this article mainly deal with the removal of the current asbestos-cement covering of the roof of the Central Market in Alicante and its replacement with zinc diamond-shaped scales, similar to the originals which were implemented in 1921 when the building was put into service. These upgrades were necessary to avoid the causes (and consequences) of rainwater infiltration, as described in an earlier report in 2006, also drafted by the author of this article. The article illustrates the difficulties involving the practical application of Spanish Code RD 396/2006 (minimum safety and health requirements for work with risk of exposure to asbestos) in a complex case such as this, especially with regard to aspects such as economic (increasing costs), technical (increased difficulty of implementation), and the total duration of the work (total increase in duration due to interference with other trades)

Evaluation of p53 codon 72 polymorphism in adenocarcinomas of the colon and rectum in La Plata, Argentina

Aim: To evaluate the potential association between p53 codon 72 polymorphism and sporadic colorectal adenocarcinoma development, and human papillomavirus (HPV) infection. Methods: One-hundred and nine controls and 53 patients with colon cancer from the city of La Plata, Argentina were analyzed. p53 codon 72 genotypes and HPV infection were identified using allele-specific polymerase chain reaction and nested polymerase chain reaction, respectively. Results: The differences in the distribution of p53 codon 72 polymorphism between the cases and controls were statistically significant. The arginine allele had a prevalence of 0.65 in controls and 0.77 in cases. The corresponding odds ratio for the homozygous arginine genotype was 2.08 (95% CI, 1.06-4.05; P<0.05). Lack of association was found between p53 polymorphism and HPV infection in the set of adenocarcinomas. Conclusion: The findings of the present study indicate that p53 codon 72 arginine homozygous genotype may represent a genetic predisposing factor for colon cancer development. However, further studies are needed in order to elucidate the role of p53 codon 72 polymorphism in colorectal cancer.Facultad de Ciencias Veterinaria

Self-assembly of Fmoc-tetrapeptides based on the RGDS cell adhesion motif

Self-assembly in aqueous solution has been investigated for two Fmoc [Fmoc ¼ N-(fluorenyl)-9-methoxycarbonyl] tetrapeptides comprising the RGDS cell adhesion motif from fibronectin or the scrambled sequence GRDS. The hydrophobic Fmoc unit confers amphiphilicity on the molecules, and introduces aromatic stacking interactions. Circular dichroism and FTIR spectroscopy show that the self-assembly of both peptides at low concentration is dominated by interactions among Fmoc units, although Fmoc-GRDS shows b-sheet features, at lower concentration than Fmoc-RGDS. Fibre X-ray diffraction indicates b-sheet formation by both peptides at sufficiently high concentration. Strong alignment effects are revealed by linear dichroism experiments for Fmoc-GRDS. Cryo-TEM and smallangle X-ray scattering (SAXS) reveal that both samples form fibrils with a diameter of approximately 10 nm. Both Fmoc-tetrapeptides form self-supporting hydrogels at sufficiently high concentration. Dynamic shear rheometry enabled measurements of the moduli for the Fmoc-GRDS hydrogel, however syneresis was observed for the Fmoc-RGDS hydrogel which was significantly less stable to shear. Molecular dynamics computer simulations were carried out considering parallel and antiparallel b-sheet configurations of systems containing 7 and 21 molecules of Fmoc-RGDS or Fmoc-GRDS, the results being analyzed in terms of both intermolecular structural parameters and energy contributions