10,343 research outputs found
Breast skin-line detection using dynamic programming
In this paper, we present a novel method to extract the breast skin-line based on dynamic programming. Skin-line extraction is an important preprocessing step in CAD systems; however, it is a challenging problem due to the presence of noise, underexposed regions, which results in a low contrast area near the skin-air interface, and artifacts such as labels. Our proposal utilizes the stroma edge to constrain searching for the border. In order to cope with noise, we consider several candidate points for the border interface which are obtained by the Laplace operator applied in pre-defined directions in the mammogram. The breast contour is obtained from the candidate points using a dynamic programming algorithm. This utilizes a criterion of optimality to obtain the optimum contour by minimization of a cost function.
The method was evaluated using 82 mammograms whose contour were manually extracted by a radiologist from the mini- MIAS database. The Polyline Distance Measure was evaluated for each contour selected with the proposed method, obtaining a mean error of 2.05 pixels and a standard deviation of 0.80.Fundação para a Ciência e a Tecnologia (FCT
Espectrometría de rayos gamma: Aplicaciones a las facies orgánicas carbonatadas del Sinemuriense–Pliensbachiense de la Cuenca Lusitánica (Portugal)
This work provides detailed information of outcrop gamma-ray logging from the Sinemurian–Pliensbachian organic-rich units (Água de Madeiros and Vale das Fontes formations) of the Lusitanian Basin, which are recognized as one of the most important potential oil source rocks interval of Portugal. The study included total and spectral gamma-ray measurements in outcrop and laboratory, Total Organic Carbon (TOC) content and whole-rock mineralogical characterization by X-ray diffraction, carried out in the two most important outcrop areas of the Western Lusitanian Basin (S. Pedro de Moel and Peniche). The outcrop data was compared with subsurface information. The results show high variability of the gamma radiation (26 to 210 cps) and radioactive elements associated with the lithological, mineralogical and geochemical differences. The TOC data yielded the organic matter enrichment of both formations, where the highest values are observed in the Água de Madeiros Formation (maximum=20.4%). The highest U concentration (11 ppm) is consistent with the highest Total Organic Carbon peak mainly supported by the precipitation of authigenic U (10 ppm). The majority of the analysed samples show an obvious authigenic U enrichment, especially in the Água de Madeiros Formation where it represents the main component of the total U content. A highly significant U/TOC correlation (r up to 0.87) with a low ratio (0.3–0.7 ppm/wt.%TOC) was obtained, confirming that U content can be used as a proxy for organic richness in the studied depositional system. The gamma-ray tool was also useful in the identification of 2nd order Transgressive–Regressive facies cycles (and maximum flooding surfaces) and in the correlation between outcrop and subsurface data.Este trabajo proporciona información detallada de espectrometría de rayos gamma de las unidades ricas en materia orgánica del Sinemuriense–Pliensbachiense de la Cuenca Lusitánica, reconocidas como los depósitos con más potencial para generar petróleo en Portugal. El estudio incluye mediciones de espectrometría de rayos gamma en afloramiento y laboratorio, cuantificación del carbono orgánico total (COT) y caracterización mineralógica por difracción de rayos X, llevada a cabo en dos áreas de la Cuenca Lusitánica (S. Pedro de Moel y Peniche). Los datos de afloramiento se han comparado con información de pozos. Los resultados muestran una alta variabilidad de la radiación gamma (26 a 210 cps), de los elementos radioactivos asociados a las distintas litologias, y de las características mineralógicas y geoquímicas. Los datos de COT evidencian un enriquecimiento en materia orgánica de toda la secuencia estudiada, en particular de la Formación de Água de Madeiros (máximo=20.4%). La concentración más elevada de U (11 ppm) es consistente con el pico principal de COT causado por la precipitación de U autigénico (10 ppm). La mayoría de las muestras analizadas presentan un marcado enriquecimiento en U autigénico, especialmente en la Formación de Água de Madeiros que representa el principal componente del contenido total de U. Se ha obtenido una correlación U/COT muy significativa (que alcanza valores de r=0.87) con una proporción baja (0.3 a 0.7 ppm/%COT), lo que confirma que el valor de la concentración de U puede ser utilizado para calcular el contenido en materia orgánica en el sistema deposicional estudiado. La técnica de rayos gamma también ha sido útil en la identificación de ciclos Transgressivo-Regressivos de 2º orden, de superficies de máxima inundación y en la correlación de datos de superficie con datos de pozos
A pesquisa em agricultura familiar no semi-arido: metodos alternativos de diagnostico e validacao de tecnologias.
Abrigando mais da metade dos estabelecimentos rurais de base familiar do pais, o Nordeste brasileiro esta ameacado de ver a maior parte desse imenso potencial de trabalho e producao desaparecer, em funcao de politicas publicas de desenvolvimento ineficazes, em termos de permitir uma efetiva insercao dessas unidades no mercado, de modo especial na regiao semi-arida. A pesquisa agricola compartilha responsabilidade nesse processo, uma vez que nao foi capaz de incorporar as suas acoes uma visao mais abrangente da problematica do agricultor familiar. Essa situacao comeca, contudo a se modificar na regiao. As experiencias de construcao de metodologias multidisciplinares e participativas adaptadas a realidades locais, comecam a se multiplicar, prenunciando a obtencao de resultados mais objetivos pela pesquisa. Tres dessas metodologias, o zoneamento municipal em unidades de desenvolvimento, o diagnostico rapido dos circuitos de comercializacao e transformacao e a validacao de tecnologias atraves dos testes de ajuste, descritas neste trabalho, sao exemplos desse esforco da pesquisa na busca de uma maior objetividade
Infestação de plantas espontâneas em cultivo de café solteiro ou consorciado com banana em sistema agroecológico.
bitstream/item/69051/1/062-germani-infestacao.pdfPublicado também no Cadernos de Agroecologia, v. 7, n.2, 2012
Projeto Gavião: impactos (meio período) do desenvolvimento rural - 1998/2001.
bitstream/item/133223/1/ID-27621.pd
Peroral esophageal segmentectomy and anastomosis with single transthoracic trocar : a step forward in thoracic NOTES.
BACKGROUND AND STUDY AIMS:
A transesophageal natural orifice transluminal endoscopic surgery (NOTES) approach has been proposed for thoracic and mediastinal access. Similarly to transgastric surgery, serious limitations remain related to creating an esophagotomy and its safe closure. A hybrid approach in thoracic NOTES could work as an intermediate step before pure transesophageal NOTES. We assessed the benefit of hybrid thoracic NOTES for peroral segmental esophagectomy and subsequent complete esophageal anastomosis with a single transthoracic port.
METHODS:
Two protocols were used to attempt esophago-esophageal anastomosis: ex vivo using a phantom model (n = 5), and in vivo after esophageal mobilization, and segmental esophagectomy achieved using either a gastroscope (flexible) (n = 5) or thoracoscope (rigid) instruments (n = 5). A forward-viewing double-channel endoscope and a transthoracic operative thoracoscope with a working channel were coordinated in order to create a complete single-layer, end-to-end esophageal anastomosis ex vivo as well as in vivo. Feasibility and anastomosis quality were evaluated by inside and outside assessment of: patency, the incorporation of mucosa in all stitches, and a leak test.
RESULTS:
Anastomosis was achieved in all ex vivo experiments and thoracoscopically-led in vivo procedures. All anastomoses were patent, allowing distal passage of the endoscope, with mucosa incorporation. In in vivo experiments, a leak was detected in three animals and corrected with additional stitching.
CONCLUSIONS:
Peroral esophageal anastomosis with a single transthoracic trocar is feasible, which may represent a step forward in thoracic NOTES
- …