Cervical cancer can be cured if detected and treated early, for which the Pap test has been fundamental. In this context, technological aids can reduce the subjective nature of the diagnosis, although there are still several issues to be solved. Here we address two of them: the identification of the cytoplasm and the nucleus in a cell image, and the determination of a set of relevant features for the detection of injured cells. In this paper we present two contributions. First, we propose an interactive segmentation method based on multispectral morphological processing in which most misleading imperfections are eliminated with a simple interaction of the analyst. Second, we made an analysis of the relevance of certain variables that characterize the relative sizes of nucleus and cytoplasm, their shapes, textures and roughness of the edges. The analysis is based on performance measures of a detector that uses feature extraction through principal component analysis (PCA) and separation of normal and injured cells by a support vector machine (SVM). We have found that minimal interaction with the physician allows for much more accurate and reliable segmentation than purely automatic methods. On the other hand, we have found that the most important characteristics for detection of injured cells are the relative sizes of the nucleus and the cytoplasm and their form, while other features, such as texture and roughness, are less relevant.

El cáncer cervical puede ser curado si se detecta y trata oportunamente, para ello la prueba Pap ha sido fundamental. En este contexto, una ayuda tecnológica puede reducir la naturaleza subjetiva del diagnóstico, pero existen dificultades en su construcción. Aquí abordamos dos de ellas: la identificación del citoplasma y el núcleo de cada célula, y la determinación de un conjunto de características relevantes para la detección de lesiones neoplásicas. En este artículo presentamos dos aportes. Primero se propone un método interactivo de segmentación basado en procesamiento morfológico multiespectral en el que las imperfecciones más engañosas de las imágenes son eliminadas con una interacción simple del analista. Segundo, se hace un análisis de la relevancia de algunas variables que caracterizan los tamaños relativos del núcleo y el citoplasma, sus formas, sus texturas y la rugosidad de sus bordes. El análisis se basa en las medidas de desempeño de un detector que utiliza extracción de características mediante análisis de componentes principales (PCA) y separación de células normales y lesionadas mediante una máquina de vectores de soporte (SVM). Encontramos que una mínima interacción con el médico permite obtener segmentaciones mucho más precisas y confiables. De otro lado, encontramos que las características más relevantes para detección de lesiones neoplásicas son los tamaños relativos del núcleo y del citoplasma y sus formas, mientras que otras características, como la textura y la rugosidad, son menos relevantes.

The paper compares and discusses displacement ductility ratios of reinforced concrete walls typically used in one- and two-story houses. Ductility is investigated by assessing response measured on 39 walls tested under shaking table excitations and quasi-static lateral loads. Variables studied were the height-to-length ratio and walls with openings, type of concrete and, steel ratio and type of web reinforcement. An equation to estimate the available ductility of a wall is proposed. Based on statistical analysis of data, values of displacement ductility capacity are recommended. Displacement ductility ratios can be used to compute both strength modification and displacement amplification factors for code-based seismic design.

Based on both ambient vibration measurements and numerical models using the wide-column analogy and the finite element method, vibrations periods of low-rise concrete dwellings are estimated in this study. A brief review of parametric and nonparametric techniques is presented and discussed, and in-situ measurements techniques are critically compared. The results of ambient vibration tests are used to calibrate numerical models. Advantages, drawbacks and accuracy of parametric techniques, as well as particular recommendations to build numerical models for assessing the elastic behavior of low-rise concrete wall dwellings, are proposed.

Los sistemas convencionales de evaluación de la citología cervicouterina presentan problemas de reproducibilidad al basarse en observaciones cualitativas, por ello, se desarrolló una metodología diagnóstica de células cervicales desde geometría fractal. A partir de las dimensiones fractales de objetos definidos en la célula, se han encontrado diferencias entre normalidad y enfermedad; además, se ha mostrado que la clasificación ASCUS (Atipias Escamosas de Significado Indeterminado) podría ser aclarada, al evidenciar su comportamiento matemático similar o bien a normalidad o a enfermedad. También, se desarrolló una generalización de dicha metodología que mostró todos los posibles prototipos, desde normalidad hasta carcinoma. A partir de la generalización desarrollada y partiendo de tres células normales, en este trabajo se realiza una simulación de posibles alteraciones celulares, desde normalidad hasta el estado de ASCUS, cuyos valores matemáticos pueden ser de normalidad o de LEIBG (Lesión Intraepitelial de Bajo Grado). Se simularon tres posibles variaciones geométricas para cada célula en el espacio de Box Counting, se calculó la dimensión fractal para núcleo, citoplasma y totalidad, manteniendo los valores de variabilidad y AMI (Armonía Matemática Intrínseca) celular. Se obtuvieron simulaciones de posibles trayectorias de normalidad a ASCUS, tanto con características de normalidad como con características de LEIBG, con medidas cuantitativas, objetivas y reproducibles. Se evidenció una organización fractal en la arquitectura de las células denominadas ASCUS, que permite el desarrollo de trayectorias acausales de alteración celular, de utilidad en la práctica clínica diaria.

Conventional systems for evaluation of cervical cytology have reproducibility problems in relying on qualitative observations. Thus a methodology was developed to diagnose cervical cells from fractal geometry. From the fractal dimensions of objects defined in the cell, it was found differences between normality and disease. Also has been shown that the classification ASCUS (Atypical Squamous Cells of Undetermined Significance) could be clarified by demonstrating its mathematical behavior similar to normal or disease. Besides, it was developed a generalization of such methodology showing all possible prototypes from normal cells to carcinoma. From the generalization developed and starting with three normal cells, in this work is made a simulation of possible cellular alterations from normality to ASCUS state whose mathematical values can be normal or LSIL (Low-grade Squamous Intraepithelial Lesion). For this, three possible geometric variations for each cell in the space of box counting was simulated, fractal dimension was calculated for nucleus, cytoplasm and whole, maintaining the values of variability and cellular AMI (Intrinsic Mathematical Harmony). Simulations of possible trajectories from normal to ASCUS were obtained, both with normal characteristics or L-SIL characteristics, with quantitative, objective and reproducible measures. It showed a fractal organization of the cell architecture called ASCUS, which allows the development of non-causal trajectories of cellular alteration useful in daily clinical practice.