Robust Speech Features based on synchrony spectrum determination using PLLs

In this work we propose to include synchrony effects, known to exist in the auditory system, to represent speech signal information in a robust way. The system decomposes the signal in a number of simpler signals, and utilizes a bank of Phase Locked Loops (PLLs) to obtain information of the frequencies present at each time. This information is interpolated in order to obtain a spectral-like representation based in synchrony effects, measured by the PLLs. Noisy speech recognition experiments are performed using this synchrony-based spectrum, which is transformed into a small set of coefficients by using a similar transformation as the one utilized for the Mel cepstrum features. We show their recognition performance compared to Mel cepstrum features obtained from the standard power spectrum. Some recognition improvements are obtained for the case of vocalic sounds for this approach, especially in the case of severe noise conditions.Sociedad Argentina de Informática e Investigación Operativ

Sistema de reconocimiento de habla en español con adaptación al discurso

Este trabajo presenta un sistema de reconocimiento automático de habla en idioma español de alto desempeño diseñado para cumplir con dos objetivos. En primer lugar, lograr tasas de reconocimiento que sean comparables a los sistemas que son estado del arte en su tipo. En segundo lugar, evaluar el desempeño de un nuevo método de estimación de modelos de lenguaje propuesto en un trabajo anterior por nuestro grupo. Los resultados muestran un porcentaje de reconocimiento cercano al 90% para un vocabulario de 5000 palabras, lo cual es del mismo orden que otros resultados reportados para sistemas de similares características pero en idioma inglés. También se verificó que el modelo de lenguaje basado en el estimador propuesto por nosotros mejora significativamente el desempeño del sistema comparado con otros dos modelos de lenguaje implementados con los mejores algoritmos conocidos.Eje: Workshop Agentes y sistemas inteligentes (WASI)Red de Universidades con Carreras en Informática (RedUNCI

Morphometric and Visual Evaluation of Fibrosis in Renal Biopsies

Interstitial fibrosis is an outcome measure of increasing importance in clinical trials of both renal transplantation and native disease, but data on the comparative advantages of fibrosis measurement methods are limited. We compared four morphometric techniques and contrasted these with two visual fibrosis-scoring methods on trichrome-stained slides. Two morphometric methods included whole-slide digital images: collagen III immunohistochemistry and a new technique using trichrome and periodic acid–Schiff subtraction morphometry; the other two methods included Sirius Red with and without polarization on multiple digital fields. We evaluated 10 serial sections from 15 renal biopsies with a range of fibrosis extent and diagnoses on duplicate sections with each method on separate days. Three pathologists performed visual scoring on whole-slide images. Visual and morphometric techniques had good to excellent interassay reproducibility (R2 = 0.62 to 0.96) and interobserver reproducibility (R2 = 0.75 to 0.99, all P < 0.001). Morphometry showed less variation between observers than visual assessment (mean of 1% to 5% versus 11% to 13%). Collagen III, Sirius Red unpolarized, and visual scores had the strongest correlations (R2 = 0.78 to 0.89), the greatest dynamic range, and the best correlation with estimated GFR (R2 = 0.38 to 0.50, P < 0.01 to 0.001). Considering efficiency, reproducibility, and functional correlation, two current techniques stand out as potentially the best for clinical trials: collagen III morphometry and visual assessment of trichrome-stained slides

Cerebral Perfusion Pressure Variability Between Patients and Between Centres

 The aim of this analysis was to investigate to what extent median cerebral perfusion pressure (CPP) differs between severe traumatic brain injury (TBI) patients and between centres, and whether the 2007 change in CPP threshold in the Brain Trauma Foundation guidelines is reflected in patient data collected at several centres over different time periods.status: publishe

Visualizing the pressure and time burden of intracranial hypertension in adult and paediatric traumatic brain injury

To assess the impact of the duration and intensity of episodes of increased intracranial pressure on 6-month neurological outcome in adult and paediatric traumatic brain injury.status: publishe

Visualizing cerebrovascular autoregulation insults and their association with outcome in adult and paediatric traumatic brain injury

Objective:  The aim of this study is to assess visually the impact of duration and intensity of cerebrovascular autoregulation insults on 6-month neurological outcome in severe traumatic brain injury. Material and methods:  Retrospective analysis of prospectively collected minute-by-minute intracranial pressure (ICP) and mean arterial blood pressure data of 259 adult and 99 paediatric traumatic brain injury (TBI) patients from multiple European centres. The relationship of the 6-month Glasgow Outcome Scale with cerebrovascular autoregulation insults (defined as the low-frequency autoregulation index above a certain threshold during a certain time) was visualized in a colour-coded plot. The analysis was performed separately for autoregulation insults occurring with cerebral perfusion pressure (CPP) below 50 mmHg, with ICP above 25 mmHg and for the subset of adult patients that did not undergo decompressive craniectomy. Results:  The colour-coded plots showed a time-intensity-dependent association with outcome for cerebrovascular autoregulation insults in adult and paediatric TBI patients. Insults with a low-frequency autoregulation index above 0.2 were associated with worse outcomes and below −0.6 with better outcomes, with and approximately exponentially decreasing transition curve between the two intensity thresholds. All insults were associated with worse outcomes when CPP was below 50 mmHg or ICP was above 25 mmHg. Conclusions:  The colour-coded plots indicate that cerebrovascular autoregulation is disturbed in a dynamic manner, such that duration and intensity play a role in the determination of a zone associated with better neurological outcome

Visualizing Cerebrovascular Autoregulation Insults and Their Association with Outcome in Adult and Paediatric Traumatic Brain Injury

Objective:  The aim of this study is to assess visually the impact of duration and intensity of cerebrovascular autoregulation insults on 6-month neurological outcome in severe traumatic brain injury. Material and methods:  Retrospective analysis of prospectively collected minute-by-minute intracranial pressure (ICP) and mean arterial blood pressure data of 259 adult and 99 paediatric traumatic brain injury (TBI) patients from multiple European centres. The relationship of the 6-month Glasgow Outcome Scale with cerebrovascular autoregulation insults (defined as the low-frequency autoregulation index above a certain threshold during a certain time) was visualized in a colour-coded plot. The analysis was performed separately for autoregulation insults occurring with cerebral perfusion pressure (CPP) below 50 mmHg, with ICP above 25 mmHg and for the subset of adult patients that did not undergo decompressive craniectomy. Results:  The colour-coded plots showed a time-intensity-dependent association with outcome for cerebrovascular autoregulation insults in adult and paediatric TBI patients. Insults with a low-frequency autoregulation index above 0.2 were associated with worse outcomes and below −0.6 with better outcomes, with and approximately exponentially decreasing transition curve between the two intensity thresholds. All insults were associated with worse outcomes when CPP was below 50 mmHg or ICP was above 25 mmHg. Conclusions:  The colour-coded plots indicate that cerebrovascular autoregulation is disturbed in a dynamic manner, such that duration and intensity play a role in the determination of a zone associated with better neurological outcome.status: publishe