63 research outputs found

    Blind source separation of multiplicative mixtures of non-stationary surface EMG signals

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    Bladder cancer and occupational exposures

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    A hospital-based cas-referent study was carried out in Lyon with the purpose of generating hypotheses about the role of occupational exposures to 320 compounds in bladder carcinogenesis. Job histories were obtained by questionnaire for 116 cases and 232 reference patients with diseases other than cancer (one referent from the same hospital ward and one from another ward of the same hospital per case) ; the referents were matched for gender, hospital, age, and nationality. Systematic coding of exposures, with a blind analysis of job histories, was carried out by a team of experts in chemistry and occupational health. Significantly elevated odds ratios were observed for exposure to pyrolysis and combustion products [odds ratio (OR) 2.3, 95 % confidence interval (95 % CI) 1.0-4.0] when the general referents were used and for cutting fluids (OR 2.6, 95 % CI 1.2-5.4) when tobacco consumption was adjusted for. The latter was highest among the category consisting of blue-collar and unskilled workers, supervisors, and agricultural workers (OR 4.6, 95 % CI 2.0-10.6), while the odds ratio for the other category was 0.8 (95 % CI 0.3-2.7). An elevated odds ratio for exposure to inks was observed for the women (OR 14.0, 95 % CI 1.8-106.5) on the basis of 14 exposed cases, but confounding factors could have been responsible for this result. Odds ratios for several other exposures (rubber : OR 5.7, nitrates : OR 8.2, coke dust : OR 3.5, meat additives : OR 3.8) were also elevated, but not significantly so when based on a small number of exposed cases. The observations of this investigation should be tested in future studies, in particular since exposures to agents such as cutting fluids or pyrolysis products are ubiquitous in industrial settings and may present an important public health hazard. (Résumé d'auteur

    Single Channel Music Sound Separation Based on Spectrogram Decomposition and Note Classification

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    Separating multiple music sources from a single channel mixture is a challenging problem. We present a new approach to this problem based on non-negative matrix factorization (NMF) and note classification, assuming that the instruments used to play the sound signals are known a priori. The spectrogram of the mixture signal is first decomposed into building components (musical notes) using an NMF algorithm. The Mel frequency cepstrum coefficients (MFCCs) of both the decomposed components and the signals in the training dataset are extracted. The mean squared errors (MSEs) between the MFCC feature space of the decomposed music component and those of the training signals are used as the similarity measures for the decomposed music notes. The notes are then labelled to the corresponding type of instruments by the K nearest neighbors (K-NN) classification algorithm based on the MSEs. Finally, the source signals are reconstructed from the classified notes and the weighting matrices obtained from the NMF algorithm. Simulations are provided to show the performance of the proposed system. © 2011 Springer-Verlag Berlin Heidelberg

    Maternal occupation during pregnancy, birth weight, and length of gestation: Combined analysis of 13 European birth cohorts

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    Objectives We assessed whether maternal employment during pregnancy – overall and in selected occupational sectors – is associated with birth weight, small for gestational age (SGA), term low birth weight (LBW), length of gestation, and preterm delivery in a population-based birth cohort design. Methods We used data from >200 000 mother-child pairs enrolled in 13 European birth cohorts and compared employed versus non-employed women. Among employees, we defined groups of occupations representing the main sectors of employment for women where potential reproductive hazards are considered to be present. The comparison group comprised all other employed women not included in the occupational sector being assessed. We performed meta-analyses of cohort-specific estimates and explored heterogeneity. Results Employees had a lower risk of preterm delivery than non-employees [adjusted odds ratio (ORadj) 0.86, 95% confidence interval (95% CI) 0.81–0.91]. Working in most of the occupational sectors studied was not associated with adverse birth outcomes. Being employed as a nurse was associated with lower risk SGA infants (ORadj 0.91, 95% CI 0.84–0.99) whereas food industry workers had an increased risk of preterm delivery (ORadj 1.50, 95% CI 1.12–2.02). There was little evidence for heterogeneity between cohorts. Conclusions This study suggests that, overall, employment during pregnancy is associated with a reduction in the risk of preterm birth and that work in certain occupations may affect pregnancy outcomes. This exploratory study provides an important platform on which to base further prospective studies focused on the potential consequences of maternal occupational exposures during pregnancy on child development

    A Bayesian approach to time-frequency based blind source separation

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