Carmen Hernández

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The vocal quality of 64 normal subjects and 57 subjects suffering various degrees of glottal cancer was investigated using acoustic measures of six different aspects of the voice signal: tone period perturbation, amplitude perturbation, waveform perturbation, vocal noise, spectral periodicity and spectral distortion. The measures were estimated taking the(More)
Mel frequency cepstral coefficients (MFCCs) are a standard tool for automatic speech recognition (ASR), but they fail to capture part of the dynamics of speech. The nonlinear nature of speech suggests that extra information provided by some nonlinear features could be especially useful when training data are scarce or when the ASR task is very complex. In(More)
We determined the secular trend in blood lead levels in a cohort of 321 children born in Mexico City between 1987 and 1992. Blood lead level was measured every 6 months during a 10-year period. We modeled the effect of yearly air lead concentration nested within the calendar year in which the child was born, family use of lead-glazed pottery, socioeconomic(More)
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