Circuitry for color coding in the primate retina.

Human color vision starts with the signals from three cone photoreceptor types, maximally sensitive to long (L-cone), middle (M-cone), and short (S-cone) wavelengths. Within the retina these signals combine in an antagonistic way to form red-green and blue-yellow spectral opponent pathways. In the classical model this antagonism is thought to arise from the convergence of cone type-specific excitatory and inhibitory inputs to retinal ganglion cells. The circuitry for spectral opponency is now being investigated using an in vitro preparation of the macaque monkey retina. Intracellular recording and staining has shown that blue-ON/yellow-OFF opponent responses arise from a distinctive bistratified ganglion cell type. Surprisingly, this cone opponency appears to arise by dual excitatory cone bipolar cell inputs: an ON bipolar cell that contacts only S-cones and an OFF bipolar cell that contacts L- and M-cones. Red-green spectral opponency has long been linked to the midget ganglion cells, but an underlying mechanism remains unclear. For example, receptive field mapping argues for segregation of L-and M-cone signals to the midget cell center and surround, but horizontal cell interneurons, believed to generate the inhibitory surround, lack opponency and cannot contribute selective L- or M-cone input to the midget cell surround. The solution to this color puzzle no doubt lies in the great diversity of cell types in the primate retina that still await discovery and analysis.

A transgene coding for a human insulin analog has a mitogenic effect on murine embryonic beta cells.

We have investigated the mitogenic effect of three mutant forms of human insulin on insulin-producing beta cells of the developing pancreas. We examined transgenic embryonic and adult mice expressing (i) human [AspB10]-proinsulin/insulin ([AspB10]ProIN/IN), produced by replacement of histidine by aspartic acid at position 10 of the B chain and characterized by an increased affinity for the insulin receptor; (ii) human [LeuA3]insulin, produced by the substitution of leucine for valine in position 3 of the A chain, which exhibits decreased receptor binding affinity; and (iii) human [LeuA3, AspB10]insulin "double" mutation. During development, beta cells of AspB10 embryos were twice as abundant and had a 3 times higher rate of proliferation compared with beta cells of littermate controls. The mitogenic effect of [AspB10]ProIN/IN was specific for embryonic beta cells because the rate of proliferation of beta cells of adults and of glucagon (alpha) cells and adrenal chromaffin cells of embryos was similar in AspB10 mice and controls. In contrast to AspB10 embryos, the number of beta cells in the LeuA3 and "double" mutant lines was similar to the number in controls. These findings indicate that the [AspB10]ProIN/IN analog increased the rate of fetal beta-cell proliferation. The mechanism or mechanisms that mediate this mitogenic effect remain to be determined.

Accelerated evolution in the protein-coding regions is universal in crotalinae snake venom gland phospholipase A2 isozyme genes.

The nucleotide sequences of four genes encoding Trimeresurus gramineus (green habu snake, crotalinae) venom gland phospholipase A2 (PLA2; phosphatidylcholine 2-acylhydrolase, EC 3.1.1.4) isozymes were compared internally and externally with those of six genes encoding Trimeresurus flavoviridis (habu snake, crotalinae) venom gland PLA2 isozymes. The numbers of nucleotide substitutions per site (KN) for the noncoding regions including introns were one-third to one-eighth of the numbers of nucleotide substitutions per synonymous site (KS) for the protein-coding regions of exons, indicating that the noncoding regions are much more conserved than the protein-coding regions. The KN values for the introns were found to be nearly equivalent to those of introns of T. gramineus and T. flavoviridis TATA box-binding protein genes, which are assumed to be a general (nonvenomous) gene. Thus, it is evident that the introns of venom gland PLA2 isozyme genes have evolved at a similar rate to those of nonvenomous genes. The numbers of nucleotide substitutions per nonsynonymous site (KA) were close to or larger than the KS values for the protein-coding regions in venom gland PLA2 isozyme genes. All of the data combined reveal that Darwinian-type accelerated evolution has universally occurred only in the protein-coding regions of crotalinae snake venom PLA2 isozyme genes.

Efeitos da diabetes mellitus e hipertensão arterial sobre a audição de idosos

Introdução: Estudos têm demonstrado que doenças crônicas e alterações metabólicas podem atuar como fator de aceleração na degeneração do sistema auditivo decorrente da idade. Todavia, os estudos sobre a associação entre a perda auditiva com o diabetes mellitus (DM) e com a hipertensão arterial (HA) em idosos mostraram conclusões controversas. Sendo assim, novos estudos sobre este assunto são necessários, a fim de esclarecer o efeito destas doenças crônicas sobre o sistema auditivo. Objetivos: Comparar uma audiometria inicial (A1) com uma audiometria sequencial (A2) realizada com um intervalo de 3 a 4 anos em uma população de idosos portadores de DM e/ou HA; realizar um estudo comparativo entre quatro grupos de idosos: grupo controle (GC), formado por idosos sem alterações crônicas, grupo de idosos portadores de DM; grupo de idosos portadores de HA, grupo de idosos portadores de DM e HA. Métodos: Foi realizado um levantamento em 901 prontuários do Estudo Longitudinal de Saúde Auditiva do Adulto (ELSAA), de indivíduos atendidos no Hospital Universitário (HU) da Universidade de São Paulo, no período de 2009 a 2015. De acordo com os critérios de inclusão, foram selecionados 100 indivíduos para participarem da presente pesquisa. A avaliação inicial (A1), constando de anamnese, audiometria tonal e imitânciometria foram utilizadas e foi feita uma nova avaliação audiológica (A2) após o período de 3 a 4 anos. Os participantes foram distribuídos em quatro grupos: 20 indivíduos portadores de DM (grupo DM), 20 indivíduos portadores de HA (grupo HA), 20 indivíduos portadores de DM e HA (grupo DMHA) e 40 indivíduos não portadores de DM nem de HA (GC). Para cada grupo estudo (HA, DM e DMHA), foram selecionados indivíduos (entre os 40 do GC) de forma a parear as características referentes a idade e sexo. Foram utilizados os testes estatísticos ANOVA, teste exato de Fisher e Kruskal-Wallis, com nível de significância de 0,05. Foi também calculada a odds ratio, com intervalo de confiança de 95%. Resultados: Não houve diferença estatisticamente significante entre as orelhas para nenhum dos grupos; sendo assim, as orelhas direita e esquerda foram agrupadas para as outras comparações. Na comparação da média de aumento anual dos limiares auditivos da primeira avaliação A1 com a segunda avaliação A2 entre os grupos, pode-se observar que para o grupo DM, não houve diferença estatisticamente significante para nenhuma das frequências avaliadas, quando comparado ao seu respectivo controle; para o grupo HA foram observadas diferenças significantes a partir de 4kHz, bem como tendência à diferença estatisticamente significante em 3 kHz, quando comparado a seu respectivo controle. Já para o grupo DMHA, quando comparado a seu grupo controle, foram observadas diferenças significantes nas frequências de 500, 2k, 3k e 8kHz, além de tendência à diferença estatisticamente significante em 4k e 6kHz. Considerando-se os casos novos de perda auditiva, pode-se observar que houve diferença estatisticamente significante apenas para o grupo HA, para as frequências altas. Verificou-se também que, para as frequências altas (3k a 8kHz), os números de casos novos de perda auditiva foram sempre maiores nos grupos estudo quando comparados aos seus respectivos controles. Na comparação das médias dos limiares auditivos, tanto na avaliação A1 quanto na avaliação A2, observou-se que os grupos estudo (DM, HA e DMHA) apresentaram limiares auditivos mais prejudicados, quando comparados a seus respectivos grupos controle. Na comparação entre os grupos apenas para a avaliação A2, pode-se observar que para as frequências altas, houve associação estatisticamente significante entre apresentar as condições clínicas (DM, HA e DMHA) e a presença de perda auditiva. A OR para DM foi de 5,57 (2,9-14,65), para HA foi de 4,2 (1,35-13,06) e para DMHA foi de 5,72 (1,85-17,64). Conclusão: Verificou-se que os idosos portadores de DM, HA ou ambos apresentaram limiares auditivos mais rebaixados quando comparados a seus respectivos grupos controle, principalmente nas altas frequências, o que sugere que estas patologias podem ter um efeito deletério sobre a audição. Além disso, nota-se que o grupo HA apresentou limiares auditivos piores para a maioria das frequências e foi o que apresentou maior queda dos limiares auditivos no segmento de 3 a 4 anos, quando comparado aos outros dois grupos estudo (DMHA e DM), sugerindo que dentre as três condições estudadas, a hipertensão parece ser a que teve maior influência sobre a audição

Incorporating global positioning data in real time P2P audio/video streams for mobile devices

We propose an original method to geoposition an audio/video stream with multiple emitters that are at the same time receivers of the mixed signal. The achieved method is suitable for those comes where a list of positions within a designated area is encoded with a degree of precision adjusted to the visualization capabilities; and is also easily extensible to support new requirements. This method extends a previously proposed protocol, without incurring in any performance penalty.

P2P audio/video protocol with global positioning data in real time for mobile devices

In this paper, we propose an original method to geoposition an audio/video stream with multiple emitters that are at the same time receivers of the mixed signal. The obtained method is suitable when a list of positions within a known area is encoded with precision tailored to the visualization capabilities of the target device. Nevertheless, it is easily adaptable to new precision requirements, as well as parameterized data precision. This method extends a previously proposed protocol, without incurring in any performance penalty.

Nueva técnica de fusión de clasificadores aplicada a la mejora de la segmentación de audio

Este artículo presenta un nuevo algoritmo de fusión de clasificadores a partir de su matriz de confusión de la que se extraen los valores de precisión (precision) y cobertura (recall) de cada uno de ellos. Los únicos datos requeridos para poder aplicar este nuevo método de fusión son las clases o etiquetas asignadas por cada uno de los sistemas y las clases de referencia en la parte de desarrollo de la base de datos. Se describe el algoritmo propuesto y se recogen los resultados obtenidos en la combinación de las salidas de dos sistemas participantes en la campaña de evaluación de segmentación de audio Albayzin 2012. Se ha comprobado la robustez del algoritmo, obteniendo una reducción relativa del error de segmentación del 6.28% utilizando para realizar la fusión el sistema con menor y mayor tasa de error de los presentados a la evaluación.

Introduction to Coding Theory for Flow Equations of Complex Systems Models

The modeling of complex dynamic systems depends on the solution of a differential equations system. Some problems appear because we do not know the mathematical expressions of the said equations. Enough numerical data of the system variables are known. The authors, think that it is very important to establish a code between the different languages to let them codify and decodify information. Coding permits us to reduce the study of some objects to others. Mathematical expressions are used to model certain variables of the system are complex, so it is convenient to define an alphabet code determining the correspondence between these equations and words in the alphabet. In this paper the authors begin with the introduction to the coding and decoding of complex structural systems modeling.

The orchestration of modes and EFL audio-visual comprehension: A multimodal discourse analysis of vodcasts

This thesis explores the role of multimodality in language learners’ comprehension, and more specifically, the effects on students’ audio-visual comprehension when different orchestrations of modes appear in the visualization of vodcasts. Firstly, I describe the state of the art of its three main areas of concern, namely the evolution of meaning-making, Information and Communication Technology (ICT), and audio-visual comprehension. One of the most important contributions in the theoretical overview is the suggested integrative model of audio-visual comprehension, which attempts to explain how students process information received from different inputs. Secondly, I present a study based on the following research questions: ‘Which modes are orchestrated throughout the vodcasts?’, ‘Are there any multimodal ensembles that are more beneficial for students’ audio-visual comprehension?’, and ‘What are the students’ attitudes towards audio-visual (e.g., vodcasts) compared to traditional audio (e.g., audio tracks) comprehension activities?’. Along with these research questions, I have formulated two hypotheses: Audio-visual comprehension improves when there is a greater number of orchestrated modes, and students have a more positive attitude towards vodcasts than traditional audios when carrying out comprehension activities. The study includes a multimodal discourse analysis, audio-visual comprehension tests, and students’ questionnaires. The multimodal discourse analysis of two British Council’s language learning vodcasts, entitled English is GREAT and Camden Fashion, using ELAN as the multimodal annotation tool, shows that there are a variety of multimodal ensembles of two, three and four modes. The audio-visual comprehension tests were given to 40 Spanish students, learning English as a foreign language, after the visualization of vodcasts. These comprehension tests contain questions related to specific orchestrations of modes appearing in the vodcasts. The statistical analysis of the test results, using repeated-measures ANOVA, reveal that students obtain better audio-visual comprehension results when the multimodal ensembles are constituted by a greater number of orchestrated modes. Finally, the data compiled from the questionnaires, conclude that students have a more positive attitude towards vodcasts in comparison to traditional audio listenings. Results from the audio-visual comprehension tests and questionnaires prove the two hypotheses of this study.