Tricromacia e a reproducao de cores em computador

This paper presents the main physical and physiological facts of Trichromacy, which is the basis of color reproduction. We present the physics of light with emphasis on the spectral characterization and its implications for color perception. The main human visual system structures are presented, with emphasis on cones responses, which are responsible for the tricromatic nature of color vision. The additive and subtractive principIes of color reproduction and their application to graphics peripherals are discussed. We emphasize aspects which make c1ear that RGB and CMY color systems are inadequate for reliable color representationEste trabalho apresenta os principais aspectos físicos e fisiológicos da Tricromacia, que é a base da reprodução de cores. Apresenta-se a base Física da luz, com ênfase na caracterização espectral e suas implicações para a percepção de cor. As principais estruturas do sistema visual humano são apresentadas, com ênfase no funcionamento dos cones, responsáveis pela natureza tricrom~tica da visão de cores. Os princípios aditivo e subtrativo para reprodução de cores são discutidos e sua utilização em alguns equipamentos gráficos comentada. Enfatiza-se aspectos referentes à representação de cor que atestam a inadequação do uso dos sistemas RGB e CMY

"Echo Offline" : uma ferramenta para medidas ecocardiográficas pós-exame

Este trabalho apresenta, de maneira condensada, o desenvolvimento de uma ferramenta computacional de apoio ao diagnóstico através de imagens ecocardiográficas, denominada de “Echo Offline”. Esta ferramenta foi projetada para mensuração de grandezas lineares em imagens ecocardiográficas digitais, possibilitando a realização de diagnósticos pós-exame e a integração dos dados colhidos no banco de dados da instituição médica. Um estudo transversal contemporâneo e aleatório foi realizado com uma população de quarenta e nove pacientes submetidos a exames ecocardiográficos, as imagens resultantes deste exame foram digitalizadas e um médico especialista mensurou um conjunto de variáveis pré-definidas utilizando o método convencional, ou seja, usando as facilidades oferecidas pelo equipamento de ultra-som comercial. Um segundo médico especialista produziu outros dois conjuntos de dados utilizando o “Echo offline” e desta forma foi possível avaliar a exatidão e a repetibilidade das medidas realizadas pela ferramenta desenvolvida. O “Echo offline” apresentou uma elevada concordância com o método convencional e apresentou significativa redução no tempo de realização das medidas

Initial steps towards a production platform for DNA sequence analysis on the grid

ABSTRACT: BACKGROUND: Bioinformatics is confronted with a new data explosion due to the availability of high throughput DNA sequencers. Data storage and analysis becomes a problem on local servers, and therefore it is needed to switch to other IT infrastructures. Grid and workflow technology can help to handle the data more efficiently, as well as facilitate collaborations. However, interfaces to grids are often unfriendly to novice users. RESULTS: In this study we reused a platform that was developed in the VL-e project for the analysis of medical images. Data transfer, workflow execution and job monitoring are operated from one graphical interface. We developed workflows for two sequence alignment tools (BLAST and BLAT) as a proof of concept. The analysis time was signicantly reduced. All workflows and executables are available for the members of the Dutch Life Science Grid and the VL-e Medical virtual organizations. All components are open source and can be transported to other grid infrastructures. CONCLUSIONS: The availability of in-house expertise and tools facilitates the usage of grid resources by new users. Our first results indicate that this is a practical, powerful and scalable solution to address the capacity and collaboration issues raised by the deployment of next generation sequencers. We currently adopt this methodology on a daily basis for DNA sequencing and other applications. More information and source code is available via http://www.bioinformaticslaboratory.nl

Automatic segmentation of cerebral infarcts in follow-up computed tomography images with convolutional neural networks

Background and purpose: Infarct volume is a valuable outcome measure in treatment trials of acute ischemic stroke and is strongly associated with functional outcome. Its manual volumetric assessment is, however, too demanding to be implemented in clinical practice. Objective: To assess the value of convolutional neural networks (CNNs) in the automatic segmentation of infarct volume in follow-up CT images in a large population of patients with acute ischemic stroke. Materials and methods: We included CT images of 1026 patients from a large pooling of patients with acute ischemic stroke. A reference standard for the infarct segmentation was generated by manual delineation. We introduce three CNN models for the segmentation of subtle, intermediate, and severe hypodense lesions. The fully automated infarct segmentation was defined as the combination of the results of these three CNNs. The results of the three-CNNs approach were compared with the results from a single CNN approach and with the reference standard segmentations. Results: The median infarct volume was 48 mL (IQR 15–125 mL). Comparison between the volumes of the three-CNNs approach and manually delineated infarct volumes showed excellent agreement, with an intraclass correlation coefficient (ICC) of 0.88. Even better agreement was found for severe and intermediate hypodense infarcts, with ICCs of 0.98 and 0.93, respectively. Although the number of patients used for training in the single CNN approach was much larger, the accuracy of the three-CNNs approach strongly outperformed the single CNN approach, which had an ICC of 0.34. Conclusion: Convolutional neural networks are valuable and accurate in the quantitative assessment of infarct volumes, for both subtle and severe hypodense infarcts in follow-up CT images. Our proposed three-CNNs approach strongly outperforms a more straightforward single CNN approach

Automatic segmentation of cerebral infarcts in follow-up computed tomography images with convolutional neural networks

Background and purpose: Infarct volume is a valuable outcome measure in treatment trials of acute ischemic stroke and is strongly associated with functional outcome. Its manual volumetric assessment is, however, too demanding to be implemented in clinical practice. Objective: To assess the value of convolutional neural networks (CNNs) in the automatic segmentation of infarct volume in follow-up CT images in a large population of patients with acute ischemic stroke. Materials and methods: We included CT images of 1026 patients from a large pooling of patients with acute ischemic stroke. A reference standard for the infarct segmentation was generated by manual delineation. We introduce three CNN models for the segmentati

The Global Impact of Science Gateways, Virtual Research Environments and Virtual Laboratories

Science gateways, virtual laboratories and virtual research environments are all terms used to refer to community-developed digital environments that are designed to meet a set of needs for a research community. Specifically, they refer to integrated access to research community resources including software, data, collaboration tools, workflows, instrumentation and high-performance computing, usually via Web and mobile applications. Science gateways, virtual laboratories and virtual research environments are enabling significant contributions to many research domains, facilitating more efficient, open, reproducible research in bold new ways. This paper explores the global impact achieved by the sum effects of these programs in increasing research impact, demonstrates their value in the broader digital landscape and discusses future opportunities. This is evidenced through examination of national and international programs in this field

Informal modernism - spontaneous building in Mexico City

Die überall aufragenden Betonstützen der unfertigen Selbstbau-Häuser sind in Mexiko-Stadt zum Symbol des spontanen Bauens geworden. Gleichzeitig haben die chaotischen Hüttensiedlungen längst einem routinierten Selbsthilfe-Städtebau Platz gemacht, der das Wohnungsproblem informell, aber gut organisiert und im großen Stil angeht. So kann man auch von einer improvisierten oder "informellen Moderne" sprechen, die sich die Menschen überall dort geschaffen haben, wo die formelle Stadtplanung und Wohnungsversorgung versagt oder auf halbem Wege stecken geblieben ist.The looming concrete columns of unfinished self-help-houses in Mexico City have become a symbol of spontaneous building worldwide. At the same time, the chaotic clusters of miserable huts have long since made way for a routinized self help urbanism, which approaches the housing problem informally, yet well organized and on a large scale. Thus one may speak of an improvised or "informal modernism" that people have created everywhere, where formal city planning and housing has either failed or gotten stuck midway

Cor : aspectos relevantes para a visualizacao de dados

Este texto apresenta os aspedos relevantes do uso de cor na geração de imagens para visualização de dados. Tópicos referentes a cor são abordados sob diférentes enfoques, apresentando os conceitos e terminologia básicos em cada caso. Inicialmente descreve-se como ocorre a manifestação de cor na energia luminosa, para depois comentar brevemente como é tratada em computadores em termos de hardware e software. Em seguida são considerados aspedos da percepção humana, salientando aqueles que originam as ilusões - cuja compreensão é muito importante para o uso controlado de cor. Por fim são apresentadas diversas recomendações sobre o uso eficiente de cor para visualização de dados, considerando as limitações de hardware e características da percepção humana. Alguns exemplos em que tais recomendações foram utilizadas são apresentados, além de conclusões acerca do panorama atual deste tema na área de Visualização Científica.This work presents the main aspeds of color usage in the generation of images for data visualization. Color concepts and terminology are presented using different approaches. We initially describe how color is considered in terms of light, and then we briefly present how it is generated in computers (hardware and software issues). We then present how color is perceived by human beings, with special emphasis on the so called illusions, whose understanding is very important to the use of color in a controlled fashion. We finally list some recommendations for the efficient use of color in data visualization, taking into account hardware and perception constraints. Examples of applications in which such recommendations were followed are considered and some conclusions about the current issues of color for Scientific Visualization aré presented