A comparative study of algorithms for automatic segmentation of dermoscopic images

Melanoma is the most common as well as the most dangerous type of skin cancer. Nevertheless, it can be effectively treated if detected early. Dermoscopy is one of the major non-invasive imaging techniques for the diagnosis of skin lesions. The computer-aided diagnosis based on the processing of dermoscopic images aims to reduce the subjectivity and time-consuming analysis related to traditional diagnosis. The first step of automatic diagnosis is image segmentation. In this project, the implementation and evaluation of several methods were proposed for the automatic segmentation of lesion regions in dermoscopic images, along with the corresponding implemented phases for image preprocessing and postprocessing. The developed algorithms include methods based on different state of the art techniques. The main groups of techniques which have been selected to be studied and implemented are thresholding-based methods, region-based methods, segmentation based on deformable models, as well as a new proposed approach based on the bag-of-words model. The implemented methods incorporate modifications for a better adaptation to features associated with dermoscopic images. Each implemented method was applied to a database constituted by 724 dermoscopic images. The output of the automatic segmentation procedure for each image was compared with the corresponding manual segmentation in order to evaluate the performance. The comparison between algorithms was carried out regarding the obtained evaluation metrics. The best results were achieved by the combination of region-based segmentation based on the multi-region adaptation of the k-means algorithm and the subIngeniería de Sistemas Audiovisuale

Límites constitucionales a la retroactividad y derogación de la denominada «Doctrina Parot»

El objeto del presente trabajo es el análisis de la reciente derogación por parte del TEDH de la denominada «Doctrina Parot» desde el punto de vista de la garantía de la irretroactividad de las disposiciones sancionadoras no favorables o restrictivas de derechos individuales establecida en el artículo 9.3 CE. Por lo tanto, en primer lugar, realizar una explicación clara y concisa de cómo está articulada en nuestro ordenamiento constitucional la retroactividad de las normas y la doctrina que en torno a ella ha elaborado el Tribunal Constitucional. Tras ello, la segunda parte del trabajo analiza el principio de irretroactividad en la sentencia del TEDH sobre el caso del Río Prada. Así, en primer lugar explico la denomina «Doctrina Parot» estudiando su nacimiento y su posterior validación por el Tribunal Constitucional para, finalmente, examinar desde el punto de vista de la retroactividad su derogación por el Tribunal Europeo de Derechos Humanos. De esta forma podremos apreciar los tres «puntos fuertes» de la «Doctrina Parot»: su nacimiento, su asentamiento en el ordenamiento jurídico español y su reciente derogación. En suma, los puntos de referencia de este trabajo son principalmente el régimen jurídico-constitucional de la retroactividad de las leyes con base principalmente en el artículo 9.3 CE, la doctrina del TEDH en materia de retroactividad ex artículo 7 CEDH y la derogación de la «Doctrina Parot

Cultivation-induced effects on the organic matter in degraded Southern African soils

15 pages, 5 figures, 2 tables, 38 references.We studied quantitative and qualitative changes in soil organic matter (SOM) due to different land uses (reference woodland versus cultivated) on six soils from Tanzania (Mkindo and Mafiga), Zimbabwe (Domboshawa and Chickwaka), and South Africa (Hertzog and Guquka). Structural characteristics of the humic acids (HAs) were measured by Curie-point pyrolysis-gas chromatography/mass spectrometry (P y-GC/MS) and solid-state 13C nuclear magnetic resonance (CPMAS 13C NMR) spectroscopy. Significant changes in concentration and composition of SOM were observed between land uses. Losses of organic carbon after cultivation ranged from 35% to 50%. Virgin soils showed large proportions of colloidal humus fractions: humic acids (HAs) and fulvic acids (FAs) but negligible amounts of not-yet decomposed organic residues. The change in land use produced a contrasting effect on the composition of the HAs: a noteworthy >alkyl enhancement> in Mkindo soil and >alkyl depletion> in Chikwaka and to a lesser extent in Domwoshawa. The remaining soils displayed only minor alterations.This work was part of an EU INCO-DEV-funded research program in southern Africa (Cyanosoils), Project ICA-4-CT-2001-10058.Peer Reviewe

Cultivation-induced effects on the organic matter in degraded Southern African soils

15 pages, 5 figures, 2 tables, 38 references.We studied quantitative and qualitative changes in soil organic matter (SOM) due to different land uses (reference woodland versus cultivated) on six soils from Tanzania (Mkindo and Mafiga), Zimbabwe (Domboshawa and Chickwaka), and South Africa (Hertzog and Guquka). Structural characteristics of the humic acids (HAs) were measured by Curie-point pyrolysis-gas chromatography/mass spectrometry (P y-GC/MS) and solid-state 13C nuclear magnetic resonance (CPMAS 13C NMR) spectroscopy. Significant changes in concentration and composition of SOM were observed between land uses. Losses of organic carbon after cultivation ranged from 35% to 50%. Virgin soils showed large proportions of colloidal humus fractions: humic acids (HAs) and fulvic acids (FAs) but negligible amounts of not-yet decomposed organic residues. The change in land use produced a contrasting effect on the composition of the HAs: a noteworthy >alkyl enhancement> in Mkindo soil and >alkyl depletion> in Chikwaka and to a lesser extent in Domwoshawa. The remaining soils displayed only minor alterations.This work was part of an EU INCO-DEV-funded research program in southern Africa (Cyanosoils), Project ICA-4-CT-2001-10058.Peer Reviewe

Wettability study and surface characterizacion by confocal laser scanning microscopy of rotary-peeled wood veneers

[ES]El objetivo de este trabajo fue estudiar las propiedades superficiales de chapas obtenidas por desenrollo de cinco especies de maderas duras: okume, ayous, chopo, fromager y eucalipto, y comparar el comportamiento de ambas caras de las chapas. Se han determinado los ángulos de contacto de equilibrio y se ha determinado la energía libre superficial de la madera así como sus componentes polar y dispersa. Asimismo, mediante microscopía de barrido láser confocal se ha evaluado la rugosidad superficial. La energía libre superficial osciló entre 49-64 mJ/m2 y disminuyó en el orden okume > fromager > chopo> ayous ~ eucalipto, lo que indica un descenso de la capacidad de mojado en ese orden. El okume con el mayor valor de la energía libre superficial y los menores valores del ángulo de contacto de equilibrio se confirmó como la especie con las mejores propiedades de mojado, siendo además la que presentó los mayores valores de los parámetros de rugosidad superficial. Comparando las propiedades superficiales para las dos caras de las chapas se encontró que dependieron de la especie, pero en general, con la excepción de la rugosidad, las diferencias no fueron muy significativas siendo los mayores cambios para las chapas de okume que presentaron un mejor mojado en su cara interior.[EN]The aim of this work was to study the surface properties of rotary-peeled veneers of five species of hardwoods: okume, ayous, poplar, fromager and eucalyptus and to compare the behavior of both sides of the veneers. The equilibrium contact angles were determined together with the wood surface free energy and its polar and disperse components. Additionally, surface roughness was evaluated using confocal laser scanning microscopy. Surface free energy ranged from 49-64 mJ/m2 and decreased in the order okume> fromager> poplar> eucalyptus ~ ayous, indicating a decrease in wettability in that order. Okume wood with the highest value of the surface free energy and the lowest values of the equilibrium contact angle was confirmed as the species with the best wetting properties, and also presented the highest values of surface roughness parameters. In general, there were not significant differences between the properties of both sides of the veneers, except for roughness. The largest differences were obtained for okume veneers whose interior side showed higher wettability

Pyrolytic characterization of humic acids in relation to carbon sequestration mechanisms in representative soils from the basque country (Northern Spain)

Comunicación y póster presentados al citado simposio, celebrado del 17-20 de septiembre, 2002, en Leoben (Austria).Curie-Point analytical pyrolysis was used for the assessment of soil organic matter accumulation processes in representative ecosystems from the Basque Country (Northem Spain). The aim of the study is to identify the main mechanisms of carbon sequestration by carrying out a semiquantitative appraisal of biogeochemical processes ranging from selective preservation of plant macromolecular material to complex processes involving extensive depolymerization of plant-inherited constituents followed by synthesis of humic-type substances.Peer reviewe

The Explanatory Models about the eukaryotic cell by secondary school students

El principal objetivo de esta investigación fue analizar los modelos explicativos del estudiantado de 8vo básico, acerca de la estructura de la célula eucarionte animal, antes y después de una intervención didáctica, fundamentada desde el Modelo Cognitivo de Ciencia (Giere, 1992) y estructurada según el Ciclo Constructivista de Aprendizaje (Sanmartí, 2000). La investigación se desarrolló en dos fases: a. En la fase descriptiva interpretativa, se categorizaron los modelos explicativos identificados en 18 familias de modelos y b. En la fase pre-experimental, se identificó sí existían diferencias significativas entre dichos modelos antes y después de la intervención didáctica a través, de las técnicas estadísticas de Wilcoxon y ANOVA de aleatoriedad de datos. Los principales hallazgos evidenciaron que la intervención didáctica favorece la construcción de modelos explicativos dinámicos y flexibles, que se caracterizan por poseer un lenguaje más especializado, establecer nuevas relaciones entre los organelos y funciones celulares, así como la capacidad de incorporar nuevos elementos para enriquecer el modelo de célula escolar, demostrando así que estos modelos se transforman progresivamente (Rodríguez y Moreira, 1999; Justi, 2006).The main objective of this study was to examine the explanatory models of secondary school students, about the structure of the animal eukaryotic cells before and after an didactic intervention, based from the cognitive model of science (Giere, 1992) and the constructivist learning cycle (Sanmartí, 2000). The research took place in two stages: a. Descriptive and interpretative stage, we categorized the explanatory models identified in 18 families of models and b. The pre-experimental stage, it identifies whether there were significant differences between the models before and after the educational intervention by Wilcoxon test and data randomization, ANOVA. The main findings showed that didactic intervention encourages the building of explanatory models, which are characterized by more specialized language, new relationships between the organelles and cellular functions and the ability to incorporate new elements to enrich the school cell model, demonstrating that these models evolve progressively (RodrÍguez and Moreira, 1999; Justi, 2006)