R. Almeida

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In this work a modified version of AMUSE, called dAMUSE, is proposed. The main modification consists in increasing the dimension of the data vectors by joining delayed versions of the observed mixed signals. With the new data a matrix pencil is computed and its generalized eigendecomposition is performed as in AMUSE. We will show that in this case the(More)
In this work we propose to assess the relation between HRV and QTV measured by an automatic delineator. A low order linear autoregressive model on RR versus QT interactions was used to explore short term relations and quantify the fractions of QTV correlated and not correlated with HRV. Power spectral density measures were estimated from the total QTV and(More)
Prolonged QT interval is considered as an index of propensity to dangerous ventricular tachyarrhythmias. The Physionet/CinC challenge 2006 encourages teams to automatically measure the QT interval of lead II's first representative beat in every record of the PTB database. A " median self-centering approach " based on manual entries to the challenge is used(More)
The main purpose of this work is to study the influence of the mechanical effect of the respiration over T wave end delineation. The performance of automatic delineation systems based in Wavelet Transform (WT) was compared, considering single lead (SL), post processing selection rules (SLR) and multi lead (ML) approaches. The T wave locations obtained over(More)
A protocol for the bacteriophage amplification technique was developed for quantitative detection of viable Listeria monocytogenes cells using the A511 listeriophage with plaque formation as the end-point assay. Laser and toluidine blue O (TBO) were employed as selective virucidal treatment for destruction of exogenous bacteriophage. Laser and TBO can bring(More)
The precision of QT interval measures depends on the correct location of QRS and T boundaries and also on the analysing lead. The usual automatic strategy to deal with multiple leads is to apply post-processing decision rules for selecting one of the single-lead (SL) measures. We proposed a multilead VCG strategy that locates the onset and the end of the QT(More)
There are evidences suggesting that spaceflight may be associated with increased susceptibility to ventricular dysrhythmias. To explore this hypothesis, five days −6° head-down bed rest (HDBR) was performed with the aim at testing the changes in QT/RR dynamics. Electrocardiogram signals (ECG) was acquired in 22 males during tilt-tests(More)
A previously proposed automatic delineation strategy for multilead (ML) location of wave boundaries is now extended to P wave boundaries. The method obtains a transformed lead by projecting the wavelet transform spatial loop into a direction that optimizes the SNR. The performance was compared with single lead delineation (SL) and with the global marks(More)