761 research outputs found
Erros em Testes e Medidas
Parece impraticável, ou demasiadamente idealista, esperar que pesquisas envolvendo testes e medidas sejam apresentadas totalmente livres de erros. o maior problema não é eliminar o erro, ao contrário, é evitar o erro que possa resultar em má interpretação dos resultados. em uma consideração mais ampla, é possível classificar erros em pesquisa como sendo resultantes de : (a) falta de lógica; (b) generalizações sem justificativa; e (c) falta de exatidão nas medidas. cada um destes aspectos têm recebido consideração de alguma forma, por parte de vários autores (Brozek & Alexander, 1947; Cureton, Wickens & Elder, 1935). O propósito da presente discussão é o de, primeiramente, considerar o erro de medidas, sua avaliação e seu controle
SCIENTIFIC, TECHNICAL AND ECONOMIC COMMITTEE FOR FISHERIES – 68th PLENARY REPORT (PLEN-21-03)
Validation of Cod maturity ogive in NAFO 3M. Effect of the reproductive ccycle moment on ogive estimation.
The Flemish Cap (FC) survey is the source of the Atlantic cod maturity data for SSB estimation. FC survey takes
place when females are resting and discrimination between spawning active and inactive females is still
possible testing the presence of postovulatory follicles, that remains several months after spawning. However,
the best moment for discriminate active spawning females is during the spawning season. For 2012 and 2014,
the maturity ogives calculated during the spawning season and when females are resting were compared.
Assuming a seasonal growth for cod in 3M, the moment in which maturity is estimated, had no effect on the
ogives estimation. Thus, it is recommended to continue employing in the 3M cod assessment the maturity
ogives produced with the FC survey information
SCIENTIFIC, TECHNICAL AND ECONOMIC COMMITTEE FOR FISHERIES – 69th PLENARY REPORT (PLEN-22-01)
Oligosacáridos utilizados para inhibir la mitosis de los astrocitos y de las células tumorales del sistema nervioso; y procedimiento de obtención de estos oligosacáridos
Traducción de Patente Europea E92923821 (fecha de solicitud, 13/11/1992).-- Prioridad: ES199111139102522.-- Titular: Consejo Superior de Investigaciones Científicas (CSIC).La invención se refiere a oligosacáridos y a preparaciones medicinales que contienen ingredientes
orgánicos activos.Peer reviewe
Lung tumorspheres as a drug screening platform against cancer stem cells
Treatment resistance and metastasis are linked to cancer stem cells (CSCs). This population represents a promising target, but remains unexplored in lung cancer. The main objective of this study was to characterize lung CSCs and discover new therapeutic strategies
Characterization of Spatiooral Cardiac Action Potential Variability at Baseline and under ß-Adrenergic Stimulation by Combined Unscented Kalman Filter and Double Greedy Dimension Reduction
Objective: Elevated spatiooral variability of human ventricular repolarization has been related to increased risk for ventricular arrhythmias and sudden cardiac death, particularly under ß-adrenergic stimulation (ß-AS). This work presents a methodology for theoretical characterization of temporal and spatial repolarization variability at baseline conditions and in response to ß-AS. For any measured voltage trace, the proposed methodology estimates the parameters and state variables of an underlying human ventricular action potential (AP) model by combining Double Greedy Dimension Reduction (DGDR) with automatic selection of biomarkers and the Unscented Kalman Filter (UKF). Such theoretical characterization can facilitate subsequent characterization of underlying variability mechanisms.
Material and Methods: Given an AP trace, initial estimates for the ionic conductances in a stochastic version of the baseline human ventricular O'Hara et al. model were obtained by DGDR. Those estimates served to initialize and update model parameter estimates by the UKF method based on formulation of an associated nonlinear state-space representation and joint estimation of model parameters and state variables. Similarly, ß-AS-induced phosphorylation levels of cellular substrates were estimated by the DGDR-UKF methodology. Performance was tested by building an experimentally-calibrated population of virtual cells, from which synthetic AP traces were generated for baseline and ß-AS conditions.
Results: The combined DGDR-UKF methodology led to 25% reduction in the error associated with estimation of ionic current conductances at baseline conditions and phosphorylation levels under ß-AS with respect to individual DGDR and UKF methods. This improvement was not at the expense of higher computational load, which was diminished by 90% with respect to the individual UKF method. Both temporal and spatial AP variability of repolarization were accurately characterized by the DGDR-UKF methodology. Conclusions: A combined DGDR-UKF methodology is proposed for parameter and state variable estimation of human ventricular cell models from available AP traces at baseline and under ß-AS. This methodology improves the estimation performance and reduces the convergence time with respect to individual DGDR and UKF methods and renders a suitable approach for computational characterization of spatiooral repolarization variability to be used for ascertainment of variability mechanisms and its relation to arrhythmogenesis
Computer Simulation of Energy Use Greenhouse Gas Emissions and Costs for Alternative Methods of Processing Fluid Milk
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