A Comparison of Front-Ends for Bitstream-Based ASR over IP

Automatic speech recognition (ASR) is called to play a relevant role in the provision of spoken interfaces for IP-based applications. However, as a consequence of the transit of the speech signal over these particular networks, ASR systems need to face two new challenges: the impoverishment of the speech quality due to the compression needed to fit the channel capacity and the inevitable occurrence of packet losses. In this framework, bitstream-based approaches that obtain the ASR feature vectors directly from the coded bitstream, avoiding the speech decoding process, have been proposed ([S.H. Choi, H.K. Kim, H.S. Lee, Speech recognition using quantized LSP parameters and their transformations in digital communications, Speech Commun. 30 (4) (2000) 223–233. A. Gallardo-Antolín, C. Pelàez-Moreno, F. Díaz-de-María, Recognizing GSM digital speech, IEEE Trans. Speech Audio Process., to appear. H.K. Kim, R.V. Cox, R.C. Rose, Performance improvement of a bitstream-based front-end for wireless speech recognition in adverse environments, IEEE Trans. Speech Audio Process. 10 (8) (2002) 591–604. C. Peláez-Moreno, A. Gallardo-Antolín, F. Díaz-de-María, Recognizing voice over IP networks: a robust front-end for speech recognition on the WWW, IEEE Trans. Multimedia 3(2) (2001) 209–218], among others) to improve the robustness of ASR systems. LSP (Line Spectral Pairs) are the preferred set of parameters for the description of the speech spectral envelope in most of the modern speech coders. Nevertheless, LSP have proved to be unsuitable for ASR, and they must be transformed into cepstrum-type parameters. In this paper we comparatively evaluate the robustness of the most significant LSP to cepstrum transformations in a simulated VoIP (voice over IP) environment which includes two of the most popular codecs used in that network (G.723.1 and G.729) and several network conditions. In particular, we compare ‘pseudocepstrum’ [H.K. Kim, S.H. Choi, H.S. Lee, On approximating Line Spectral Frequencies to LPC cepstral coefficients, IEEE Trans. Speech Audio Process. 8 (2) (2000) 195–199], an approximated but straightforward transformation of LSP into LP cepstral coefficients, with a more computationally demanding but exact one. Our results show that pseudocepstrum is preferable when network conditions are good or computational resources low, while the exact procedure is recommended when network conditions become more adverse.Publicad

Species-specific relationships between water transparency and male coloration within and between two closely related Lake Victoria cichlid species

Environmental variation in signalling conditions affects animal communication traits, with possible consequences for sexual selection and reproductive isolation. Using spectrophotometry, we studied how male coloration within and between populations of two closely related Lake Victoria cichlid species (Pundamilia pundamilia and P. nyererei) covaries with water transparency. Focusing on coloration patches implicated in sexual selection, we predicted that in clear waters, with broad-spectrum light, (1) colours should become more saturated and (2) shift in hue away from the dominant ambient wavelengths, compared to more turbid waters. We found support for these predictions for the red and yellow coloration of P. nyererei but not the blue coloration of P. pundamilia. This may be explained by the species difference in depth distribution, which generates a steeper gradient in visual conditions for P. nyererei compared to P. pundamilia. Alternatively, the importance of male coloration in intraspecific sexual selection may differ between the species. We also found that anal fin spots, that is, the orange spots on male haplochromine anal fins that presumably mimic eggs, covaried with water transparency in a similar way for both species. This is in contrast to the other body regions studied and suggests that, while indeed functioning as signals, these spots may not play a role in species differentiation.</p

Benefits of an educational program for journalists on media coverage of HIV/AIDS in developing countries

Benefits of an educational program for journalists on medi

Fluid–structure interaction simulations outperform computational fluid dynamics in the description of thoracic aorta haemodynamics and in the differentiation of progressive dilation in Marfan syndrome patients

Abnormal fluid dynamics at the ascending aorta may be at the origin of aortic aneurysms. This study was aimed at comparing the performance of computational fluid dynamics (CFD) and fluid–structure interaction (FSI) simulations against four-dimensional (4D) flow magnetic resonance imaging (MRI) data; and to assess the capacity of advanced fluid dynamics markers to stratify aneurysm progression risk. Eight Marfan syndrome (MFS) patients, four with stable and four with dilating aneurysms of the proximal aorta, and four healthy controls were studied. FSI and CFD simulations were performed with MRI-derived geometry, inlet velocity field and Young's modulus. Flow displacement, jet angle and maximum velocity evaluated from FSI and CFD simulations were compared to 4D flow MRI data. A dimensionless parameter, the shear stress ratio (SSR), was evaluated from FSI and CFD simulations and assessed as potential correlate of aneurysm progression. FSI simulations successfully matched MRI data regarding descending to ascending aorta flow rates (R2 = 0.92) and pulse wave velocity (R2 = 0.99). Compared to CFD, FSI simulations showed significantly lower percentage errors in ascending and descending aorta in flow displacement (−46% ascending, −41% descending), jet angle (−28% ascending, −50% descending) and maximum velocity (−37% ascending, −34% descending) with respect to 4D flow MRI. FSI- but not CFD-derived SSR differentiated between stable and dilating MFS patients. Fluid dynamic simulations of the thoracic aorta require fluid–solid interaction to properly reproduce complex haemodynamics. FSI- but not CFD-derived SSR could help stratifying MFS patients.This study was funded by Ministerio de Economía y Competitividad (grant no. RTC-2016-5152-1), Fundació la Marató de TV3 (grant no. 20151330), FP7 People: Marie-Curie Actions (grant no. 267128), Instituto de Salud Carlos III (grant nos PI14/0106 and PI17/00381) and ‘la Caixa’ Foundation. M.V. was funded by CompBioMed2, grant agreement ID: 823712, funded under: H2020-EU.1.4.1.3; and SILICOFCM, grant agreement ID: 777204, funded under: H2020-EU.3.1.5.Peer ReviewedPostprint (published version

Resistencia a fármacos en pacientes en tratamiento antirretroviral, Cali, Colombia, 2008-2010

Introduction: Little has been published in Colombia on HIV drug resistance in patients taking antiretroviral treatment (ART). Currently, the Colombian guidelines do not recommend the use of genotypic antiretroviral resistance tests (GART) for treatment-naive patients or for those experiencing a first therapeutic failure.Objective: To determine the frequency of relevant resistance mutations and the degree of susceptibility/resistance of HIV to antiretroviral drugs (ARVs) in ART-experienced patients.Materials and methods: A non-random sample of 170 ART-experienced HIV patients with virologic failure and who underwent GART was recruited. A study of HIV drug resistance was carried out in two groups of patients: one group that underwent early GART and the other group that received late GART testing.Results: The most frequent type of resistance affected the non-nucleoside class (76%). The late-GART group had higher risk of nucleoside analog and protease inhibitor drug resistance, a higher number of  resistance mutations and more complex mutational profiles than the early-GART group. A high cross resistance level (30%) was found in the nucleoside analog class. The least affected medications were tenofovir and darunavir.Conclusions: Our results suggest that performing GART late is associated with levels of ARV resistance that could restrict the use of an important number of essential ARV in subsequent regimens. There is a need to revise the current recommendations to include GART prior to start of treatment and after the first virologic failure. doi: http://dx.doi.org/10.7705/biomedica.v33i4.1462Introducción. En Colombia se ha publicado poco sobre farmacorresistencia del VIH en pacientes que toman tratamiento antirretroviral (TAR). Las guías de VIH de Colombia de 2006 no recomiendan el uso de los estudios genotípicos de resistencia (EGR) en pacientes nunca expuestos a medicamentos antirretrovirales ni después del primer fracaso terapéutico. Objetivo. Determinar la frecuencia de mutaciones de resistencia y el grado de susceptibilidad/resistencia del VIH a los antirretrovirales en pacientes expuestos a TAR. Materiales y métodos. Se reclutó una muestra no probabilística de 170 pacientes con infección por VIH que tomaban TAR, experimentaban fracaso virológico y que tenían EGR. Se estudió la farmacorresistencia del VIH en dos grupos: EGR temprano vs. EGR tardío.Resultados. El tipo de resistencia más frecuente en pacientes que toman TAR afectó a los inhibidores no nucleosídicos (76%). El grupo tardío tuvo mayor riesgo de resistencia a inhibidores nucleosídicos y a los inhibidores de proteasa, mayor número de mutaciones de resistencia y mayor complejidad de las resistencias que el grupo temprano. También se encontró un alto grado (30%) de resistencia cruzada a los inhibidores nucleosídicos en el grupo tardío. Los medicamentos menos afectados fueron tenofovir y darunavir. Conclusiones. Los resultados de este estudio sugieren que realizar EGR tardíos se asocia a altos niveles de resistencia, lo cual puede restringir el uso de un gran número de ARVs esenciales en regímenes subsiguientes. Es necesario revisar las actuales recomendaciones sobre el uso de EGR en las guías Colombianas de manejo de VIH.   doi: http://dx.doi.org/10.7705/biomedica.v33i4.146

Technology as 'Applied Science': a Serious Misconception that Reinforces Distorted and Impoverished Views of Science

The current consideration of technology as 'applied science', this is to say, as something that comes 'after' science, justifies the lack of attention paid to technology in science education. In our paper we question this simplistic view of the science-technology relationship, historically rooted in the unequal appreciation of intellectual and manual work, and we try to show how the absence of the technological dimension in science education contributes to a na¿ ve and distorted view of science which deeply affects the necessary scientific and technological literacy of all citizens

A Template-Dependent Dislocation Mechanism Potentiates K65R Reverse Transcriptase Mutation Development in Subtype C Variants of HIV-1

Numerous studies have suggested that the K65R reverse transcriptase (RT) mutation develops more readily in subtype C than subtype B HIV-1. We recently showed that this discrepancy lies partly in the subtype C template coding sequence that predisposes RT to pause at the site of K65R mutagenesis. However, the mechanism underlying this observation and the elevated rates of K65R development remained unknown. Here, we report that DNA synthesis performed with subtype C templates consistently produced more K65R-containing transcripts than subtype B templates, regardless of the subtype-origin of the RT enzymes employed. These findings confirm that the mechanism involved is template-specific and RT-independent. In addition, a pattern of DNA synthesis characteristic of site-specific primer/template slippage and dislocation was only observed with the subtype C sequence. Analysis of RNA secondary structure suggested that the latter was unlikely to impact on K65R development between subtypes and that Streisinger strand slippage during DNA synthesis at the homopolymeric nucleotide stretch of the subtype C K65 region might occur, resulting in misalignment of the primer and template. Consequently, slippage would lead to a deletion of the middle adenine of codon K65 and the production of a -1 frameshift mutation, which upon dislocation and realignment of the primer and template, would lead to development of the K65R mutation. These findings provide additional mechanistic evidence for the facilitated development of the K65R mutation in subtype C HIV-1

The Origin and Evolutionary History of HIV-1 Subtype C in Senegal

Background: The classification of HIV-1 strains in subtypes and Circulating Recombinant Forms (CRFs) has helped in tracking the course of the HIV pandemic. In Senegal, which is located at the tip of West Africa, CRF02_AG predominates in the general population and Female Sex Workers (FSWs). In contrast, 40% of Men having Sex with Men (MSM) in Senegal are infected with subtype C. In this study we analyzed the geographical origins and introduction dates of HIV-1 C in Senegal in order to better understand the evolutionary history of this subtype, which predominates today in the MSM population Methodology/Principal Findings: We used a combination of phylogenetic analyses and a Bayesian coalescent-based approach, to study the phylogenetic relationships in pol of 56 subtype C isolates from Senegal with 3,025 subtype C strains that were sampled worldwide. Our analysis shows a significantly well supported cluster which contains all subtype C strains that circulate among MSM in Senegal. The MSM cluster and other strains from Senegal are widely dispersed among the different subclusters of African HIV-1 C strains, suggesting multiple introductions of subtype C in Senegal from many different southern and east African countries. More detailed analyses show that HIV-1 C strains from MSM are more closely related to those from southern Africa. The estimated date of the MRCA of subtype C in the MSM population in Senegal is estimated to be in the early 80's. Conclusions/Significance: Our evolutionary reconstructions suggest that multiple subtype C viruses with a common ancestor originating in the early 1970s entered Senegal. There was only one efficient spread in the MSM population, which most likely resulted from a single introduction, underlining the importance of high-risk behavior in spread of viruses

Can an Infectious Disease Genomics Project Predict and Prevent the Next Pandemic?

Infectious diseases need a globally coordinated genomic-based movement linking sequencing efforts to development of response tools to mitigate the impact of existing and emerging threats