6,657 research outputs found

    Breast skin-line detection using dynamic programming

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    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

    Espectrometr√≠a de rayos gamma: Aplicaciones a las facies org√°nicas carbonatadas del Sinemuriense‚ÄďPliensbachiense de la Cuenca Lusit√°nica (Portugal)

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    This work provides detailed information of outcrop gamma-ray logging from the Sinemurian‚ÄďPliensbachian organic-rich units (√Āgua 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 √Āgua 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 √Āgua 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‚Äď0.7 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‚ÄďRegressive facies cycles (and maximum flooding surfaces) and in the correlation between outcrop and subsurface data.Este trabajo proporciona informaci√≥n detallada de espectrometr√≠a de rayos gamma de las unidades ricas en materia org√°nica del Sinemuriense‚ÄďPliensbachiense de la Cuenca Lusit√°nica, reconocidas como los dep√≥sitos con m√°s potencial para generar petr√≥leo en Portugal. El estudio incluye mediciones de espectrometr√≠a de rayos gamma en afloramiento y laboratorio, cuantificaci√≥n del carbono org√°nico total (COT) y caracterizaci√≥n mineral√≥gica por difracci√≥n de rayos X, llevada a cabo en dos √°reas de la Cuenca Lusit√°nica (S. Pedro de Moel y Peniche). Los datos de afloramiento se han comparado con informaci√≥n de pozos. Los resultados muestran una alta variabilidad de la radiaci√≥n gamma (26 a 210 cps), de los elementos radioactivos asociados a las distintas litologias, y de las caracter√≠sticas mineral√≥gicas y geoqu√≠micas. Los datos de COT evidencian un enriquecimiento en materia org√°nica de toda la secuencia estudiada, en particular de la Formaci√≥n de √Āgua de Madeiros (m√°ximo=20.4%). La concentraci√≥n m√°s elevada de U (11 ppm) es consistente con el pico principal de COT causado por la precipitaci√≥n de U autig√©nico (10 ppm). La mayor√≠a de las muestras analizadas presentan un marcado enriquecimiento en U autig√©nico, especialmente en la Formaci√≥n de √Āgua de Madeiros que representa el principal componente del contenido total de U. Se ha obtenido una correlaci√≥n U/COT muy significativa (que alcanza valores de r=0.87) con una proporci√≥n baja (0.3 a 0.7 ppm/%COT), lo que confirma que el valor de la concentraci√≥n de U puede ser utilizado para calcular el contenido en materia org√°nica en el sistema deposicional estudiado. La t√©cnica de rayos gamma tambi√©n ha sido √ļtil en la identificaci√≥n de ciclos Transgressivo-Regressivos de 2¬ļ orden, de superficies de m√°xima inundaci√≥n y en la correlaci√≥n de datos de superficie con datos de pozos

    A pesquisa em agricultura familiar no semi-arido: metodos alternativos de diagnostico e validacao de tecnologias.

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    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

    Impact of atomic layer deposited TiO2 on the photocatalytic efficiency of TiO2/w-VA-CNT nanocomposite materials

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    Titanium oxide (TiO2) has been widely investigated as a photocatalytic material, and the fact that its performance depends on its crystalline structure motivates further research on the relationship between preparation methods and material properties. In this work, TiO2 thin films were grown on non- functionalized wave-like patterned vertically aligned carbon nanotubes (w-VA-CNTs) via the atomic layer deposition (ALD) technique. Grazing incidence X-ray diffraction (GIXRD) analysis revealed that the structure of the TiO2/VA-CNT nanocomposites varied from amorphous to a crystalline phase with increasing deposition temperature, suggesting a ‚Äúcritical deposition temperature‚ÄĚ for the anatase crystalline phase formation. On the other hand, scanning transmission electron microscopy (STEM) studies revealed that the non-functionalized carbon nanotubes were conformally and homogeneously coated with TiO2, forming a nanocomposite while preserving the morphology of the nanotubes. X-ray photoelectron spectroscopy (XPS) provided information about the surface chemistry and stoichiometry of TiO2. The photodegradation experiments under ultraviolet (UV) light on a model pollutant (Rhodamine B, RhB) revealed that the nanocomposite comprised of anatase crystalline TiO2 grown at 200 ?C (11.2 nm thickness) presented the highest degradation efficiency viz 55% with an illumination time of 240 min. Furthermore, its recyclability was also demonstrated for multiple cycles, showing good recovery and potential for practical applications.publishe

    Projeto Gavião: impactos (meio período) do desenvolvimento rural - 1998/2001.

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    Infesta√ß√£o de plantas espont√Ęneas em cultivo de caf√© solteiro ou consorciado com banana em sistema agroecol√≥gico.

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    bitstream/item/69051/1/062-germani-infestacao.pdfPublicado também no Cadernos de Agroecologia, v. 7, n.2, 2012

    In vivo assessment of gastrotomy closure with over-the-scope clips in an experimental model for varicocelectomy

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    BACKGROUND: Gastrotomy closure remains the major limiting factor for human translation of transgastric surgery; the over-the-scope clip (OTSC) system was proposed as a possibility for this purpose. Transgastric access is good for a pelvic approach, making varicocelectomy a possible indication for natural orifice transluminal endoscopic surgery (NOTES). OBJECTIVE: To evaluate the reliability of the OTSC system in vivo after transgastric testicular vessel ligation (varicocelectomy model). DESIGN: There were 3 experimental groups (5 animals in each): groups 1 and 3, gastrotomy dilation up to 18 mm, surgery was performed with a double-channel endoscope; group 2, gastrotomy dilation up to 13 mm, surgery was performed with a single-channel endoscope. SETTING: Surgical Sciences Research Domain, Life and Health Sciences Research Institute (ICVS), School of Health Sciences, University of Minho, Braga, Portugal. INTERVENTIONS: Bilateral testicular vessel ligation by transgastric access. Gastrotomy closed with the largest version of OTSC system (12 mm): a single clip in groups 1 and 2, and 2 clips in group 3. Animals were monitored for 2 weeks, killed, and submitted for necropsy. MAIN OUTCOME MEASUREMENTS: Adequacy of closure and healing after the use of the OTSC system. Statistical analysis. RESULTS: Vessel ligation was easily achieved in all groups. Although differences in the complication rate did not reach statistical significance (P = .099), there was a clear tendency for a better prognosis in groups 2 and 3 than group 1. In fact, only 2 animals from group 1 had complications related to incomplete gastrotomy closure. LIMITATIONS: Small number of animals per group; nonrandomized study. CONCLUSIONS: The OTSC system was shown to be easy and efficient for gastrotomy closure in a survival experimental model of varicocelectomy, when correctly matching the gastrotomy size with the clip size and/or number
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