94 research outputs found

    LIMITES E POSSIBILIDADES DE MELHORIA DOS PROGRAMAS DE WHISTLEBLOWERS PARA O COMBATE À CORRUPÇÃO NO BRASIL

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    Este artigo faz uma análise dos programas de whistleblowers, partindo da sua origem no direito norte-americano, Europeu até a sua consolidação no cenário internacional. Parte-se da premissa que o programa de proteção de denunciantes é essencial para o avanço do combate a corrupção no Brasil. A metodologia consiste em examinar os elementos normativos e comportamentais que configuram a estrutura e a efetividade destes programas, explicar como o tema se desenvolveu em vários países no mundo. Em seguida, mostrar quais os principais pontos que foram objeto de aperfeiçoamento nos demais países e discutidos no tribunais internacionais. Depois, como o tema foi construído no Brasil. Por fim, a luz das experiências internacionais e das discussões na ENCCLA, propor melhorias à legislação brasileira. Conclui-se que o o programa de proteção de testemunhas precisa ser aperfeiçoado, em virtude das experiências encontradas na sua implementação e propõe tais alterações

    Narrative-based computational modelling of the Gp130/JAK/STAT signalling pathway.

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    BACKGROUND: Appropriately formulated quantitative computational models can support researchers in understanding the dynamic behaviour of biological pathways and support hypothesis formulation and selection by "in silico" experimentation. An obstacle to widespread adoption of this approach is the requirement to formulate a biological pathway as machine executable computer code. We have recently proposed a novel, biologically intuitive, narrative-style modelling language for biologists to formulate the pathway which is then automatically translated into an executable format and is, thus, usable for analysis via existing simulation techniques. RESULTS: Here we use a high-level narrative language in designing a computational model of the gp130/JAK/STAT signalling pathway and show that the model reproduces the dynamic behaviour of the pathway derived by biological observation. We then "experiment" on the model by simulation and sensitivity analysis to define those parameters which dominate the dynamic behaviour of the pathway. The model predicts that nuclear compartmentalisation and phosphorylation status of STAT are key determinants of the pathway and that alternative mechanisms of signal attenuation exert their influence on different timescales. CONCLUSION: The described narrative model of the gp130/JAK/STAT pathway represents an interesting case study showing how, by using this approach, researchers can model biological systems without explicitly dealing with formal notations and mathematical expressions (typically used for biochemical modelling), nevertheless being able to obtain simulation and analysis results. We present the model and the sensitivity analysis results we have obtained, that allow us to identify the parameters which are most sensitive to perturbations. The results, which are shown to be in agreement with existing mathematical models of the gp130/JAK/STAT pathway, serve us as a form of validation of the model and of the approach itself

    Stochastic Simulation of Process Calculi for Biology

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    Biological systems typically involve large numbers of components with complex, highly parallel interactions and intrinsic stochasticity. To model this complexity, numerous programming languages based on process calculi have been developed, many of which are expressive enough to generate unbounded numbers of molecular species and reactions. As a result of this expressiveness, such calculi cannot rely on standard reaction-based simulation methods, which require fixed numbers of species and reactions. Rather than implementing custom stochastic simulation algorithms for each process calculus, we propose to use a generic abstract machine that can be instantiated to a range of process calculi and a range of reaction-based simulation algorithms. The abstract machine functions as a just-in-time compiler, which dynamically updates the set of possible reactions and chooses the next reaction in an iterative cycle. In this short paper we give a brief summary of the generic abstract machine, and show how it can be instantiated with the stochastic simulation algorithm known as Gillespie's Direct Method. We also discuss the wider implications of such an abstract machine, and outline how it can be used to simulate multiple calculi simultaneously within a common framework.Comment: In Proceedings MeCBIC 2010, arXiv:1011.005

    Long-term functional outcome after laryngeal cancer treatment.

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    BACKGROUND The functional outcome after the treatment of laryngeal cancer is tightly related to the quality of life of affected patients. The aim of this study is to describe the long-term morbidity and functional outcomes associated with the different treatment modalities for laryngeal cancer. METHODS Retrospective chart review of 477 patients undergoing curatively intended treatment for laryngeal cancer at our tertiary referral center from 2001 to 2014: Details on patient and disease characteristics, diagnostics and treatment related functional outcomes were analyzed. RESULTS With a median follow-up of 51 months, the crude rate of functional larynx preservation was 74.6%. Radiotherapy +/- chemotherapy was the dominant treatment modality (n = 359-75.3%), whereas 24.7% (n = 118) underwent primary surgery, with 58.5% (69) receiving adjuvant treatment. The 5-year laryngectomy-free survival was 57% (95% CI, 48-66%) after surgery vs. 69% (95% CI, 64-75%) after chemoradiotherapy (p < 0.01). In stage III-IVB, these rates were 26% (95% CI, 16-39%) vs. 47% (95% CI, 36-59%), respectively (p < 0.01). Aspiration occurred in 7%, tracheostomy was necessary in 19.8% and feeding tube placement in 25.4%. Feeding tube and tracheostomy necessity was higher in the initially surgically treated group. Primary surgery (HR: 1.67, 95% CI: 1.19-2.32; p < 0.01), stage III-IVB (HR: 4.07, 95% CI: 2.97-5.60; p < 0.01) and tumor recurrence (HR: 3.83, 95% CI: 2.79-5.28; p < 0.01) remained as adverse factors for laryngectomy-free survival. CONCLUSIONS Preserving the laryngeal function after cancer treatment is challenging. Advanced tumor stages, primary surgery and recurrence are related to a poor functional outcome. Therefore, the criteria for initial decision-making needs to be further refined

    Snazer: the simulations and networks analyzer

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    <p>Abstract</p> <p>Background</p> <p>Networks are widely recognized as key determinants of structure and function in systems that span the biological, physical, and social sciences. They are static pictures of the interactions among the components of complex systems. Often, much effort is required to identify networks as part of particular patterns as well as to visualize and interpret them.</p> <p>From a pure dynamical perspective, simulation represents a relevant <it>way</it>-<it>out</it>. Many simulator tools capitalized on the "noisy" behavior of some systems and used formal models to represent cellular activities as temporal trajectories. Statistical methods have been applied to a fairly large number of replicated trajectories in order to infer knowledge.</p> <p>A tool which both graphically manipulates reactive models and deals with sets of simulation time-course data by aggregation, interpretation and statistical analysis is missing and could add value to simulators.</p> <p>Results</p> <p>We designed and implemented <it>Snazer</it>, the simulations and networks analyzer. Its goal is to aid the processes of visualizing and manipulating reactive models, as well as to share and interpret time-course data produced by stochastic simulators or by any other means.</p> <p>Conclusions</p> <p><it>Snazer </it>is a solid prototype that integrates biological network and simulation time-course data analysis techniques.</p

    Estudos sobre a nutrição mineral do sorgo granífero: VI. absorção de fosfato por raizes destacadas de plantas de três variedades comerciais

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    Experiments were carried out in order to study the effect of time external concentration, pH, temperature, aeration and inhibitors (KF, KCN and 2,4-DNP) on the phosphate absorption by the excised roots of grain Sorghum bicolor L. Moench var. Contibrasil 102, DeKalb and Tey-101, using 32P as tracer.Foi estudada a absorção de fosfato marcado com 32P por raizes destacadas de três variedades de sorgo granífero. A influência do tempo, concentração iônica externa, pH, aeração, venenos respiratórios e desacopladores de fosforilação oxidativa foi considerada; o estudo da cinéstica da absorção mostrou diferenças entre as variedades nos parâmetros michaelianos
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