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Copyright of Revista Facultad de Ciencias Basicas is the property of Revista Facultad de Ciencias Basicas and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

BACKGROUND: Nonlinear dynamics have allowed the development of diagnostic methodologies of cardiac dynamics and the evaluation of the behavior of different hemodynamic variables. OBJECTIVE: To characterize the chaotic behavior of the heart rate and parameters of the blood gases of patients of the intensive care unit within the framework of dynamic systems theory. MATERIAL AND METHOD: A study was done including clinical reports of blood gases and continuous electrocardiographic records were selected from patients of the intensive care unit. Heart rate, pressure of arterial and venous carbon dioxide, and venous oxygen saturation were systematized. Then, chaotic attractors of these variables were generated in the delay map, and the maximum and minimum values of the attractors were established. RESULTS: There were included 25 clinical reports. The minimum and maximum values of the attractors of venous oxygen saturation were between 22.1 and 97.3%. The minimum and maximum values of the attractors of PaCO2 were between 17 and 97.9 mmHg. The minimum and maximum values of the attractors of PvCO2 ranged from 14.4 to 64.1 mmHg. Heart rate values were found between 62 and 210 lat/min. CONCLUSIONS: It was possible to characterize the chaotic behavior of the parameters of blood gases and heart rate, in the context of dynamic systems theory. [ABSTRACT FROM AUTHOR]

In this study, Multifractal Detrended Fluctuation Analysis (MFDFA) is applied to daily temperature time series in Benin synoptic stations from 1967 to 2012. The purpose is to examine the degree of multifractality and compare multifractal characteristics of temperature in various climatic areas (subequatorial and Sudanian). The analysis reveals that the daily temperature time series shows a multifractal behavior that is sensitive to the station's geographic position and presents a positive long-term correlation. Weather conditions and the geographic position of the synoptic stations affect the shape and the characteristics of temperature spectrum. The multifractality is stronger in subequatorial region than the Sudanian. The major source of multifractality in temperature series is found to be the fat-tailed probability density function. However, long-range correlations also partly contribute to the multifractal features. Except Kandi's synoptic station, the spectrum is left-skewed. The findings indicate the usefulness of the non-linear analysis in climate research due to the complex interactions among the natural processes. It can help understand the mechanisms governing the dynamics of temperature time series in Benin. [ABSTRACT FROM AUTHOR]

Supporting earthquake risk management with clear seismic communication may necessitate encounters with various popular misapprehensions regarding earthquake prediction. Drawing on technical data as well as insights from anthropology and economics, this paper addresses common and scientifically-unsupported ideas about earthquake prediction, as well as the state of science-based studies regarding statistical forecasting and physical precursors. The authors reflect on documented social and economic effects of unsubstantiated earthquake predictions, and argue that these may be dangerous but may also present certain opportunities for outreach and education in formal and informal settings. This paper is written in light of the importance that the United Nations Office for Disaster Risk Reduction has placed on coordination and communication within and among diverse organizations and agencies as well as by the recent popularity of so-called earthquake prediction in Mexico. [ABSTRACT FROM AUTHOR]

El descubrimiento de nuevos resultados fundamentales en dinámica no lineal y su rápida difusión han proporcionado a la economía herramientas de análisis y el enfoque necesario para abordar con mayor rigor matemático algunos de los difíciles problemas relacionados con la inestabilidad y las fluctuaciones. Existe un consenso amplio entre los economistas acerca de la enorme dificultad presente a la hora de explicar los ciclos económicos, de hecho, a lo largo de los dos últimos siglos se han propuesto multitud de modelos que intentan describir este comportamiento.

Este artículo presenta un sistema para la detección automática de señales de voz hipernasales basado en la combinación de dos diferentes esquemas de caracterización aplicados en las cinco vocales del español y dos palabras seleccionadas. El primer esquema está basado en características clásicas como perturbaciones del periodo fundamental, medidas de ruido y coeficientes cepstrales en la frecuencia de Mel. El segundo enfoque está basado en medidas de dinámica no lineal. Las características más relevantes son seleccionadas usando dos técnicas: análisis de componentes principales y selección flotante hacia adelante secuencial. La decisión acerca de si un registro de voz es hipernasal o sano es tomada usando una máquina de soporte vectorial de margen suave. Los experimentos consideran grabaciones de las cinco vocales del idioma español y las palabras y se consideran, asimismo, tres conjuntos de características: (1) el enfoque clásico, (2) el análisis de dinámica no lineal y (3) la combinación de ambos esquemas. En general, los aciertos son mayores y más estables cuando las características clásicas y no lineales son combinadas, indicando que el análisis de dinámica no lineal se complementa con el esquema clásico.

Un aspecto esencial en la enseñanza de la física es la búsqueda de vías para familiarizar a los estudiantes con temas de actualidad. Uno de esos temas es el de Dinámica No Lineal, de gran interés en múltiples campos de la ciencia y la tecnología. En publicaciones relativas a la enseñanza de la física se han abordado diversas facetas del tema, sin embargo, las actividades a realizar por los propios estudiantes en un curso inicial de física requieren aún elaboración. En este trabajo se describe el sistema de actividades utilizado en el primer año de la carrera de Física Nuclear del Instituto Superior de Tecnologías y Ciencias Aplicadas de Cuba. Las actividades se han agrupado alrededor de los conceptos de sistema no lineal, espacio de fases, atractor y caos determinista. La calidad de los informes que confeccionan los estudiantes y el interés de ellos confirman la viabilidad de las actividades.

Copyright of Texto & Contexto Enfermagem is the property of Universidade Federal de Santa Catarina, Programa de Pos-Graduacao de Enfermagem and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This article presents a system of three first-orden ordinary differential equations to study the dynamic interaction between renewable resources, population and environmental pollution in a region. The model is achieved coupling a dynamic equation of contamination to formulated systems by Simone D'alessandro and shows that under the Hopf bifurcation can be found conditions to achieve sustainable development under the definition given in the report of Brundtland commission 1987. That is, when a harmonic balance between the state variables of the model is reached. [ABSTRACT FROM AUTHOR]

Copyright of Cuaderno Activa is the property of Tecnologico de Antioquia, Institucion Universitari and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Se analiza la dinámica y estabilidad en la producción de butanol por fermentación en un biorreactor continuo. La respuesta dinámica del sistema se estudió eligiendo como criterio de evaluación la concentración de butanol, en un modelo cinético validado estadísticamente, que describe el comportamiento oscilatorio de cultivos continuos teniendo en cuenta la influenciadel pH, inhibición por productos y los parámetros influyentes en el sistema. Se tomaron como parámetros de bifurcación la dilución (D) y la concentración de sustrato de alimentación (Sf). Se empleó una rutina de cálculo en Matlab® y la herramienta Matcont® para generar diagramas de comportamiento dinámico, valores de estado estacionario y diagramas de bifurcación. Los resultados muestran que es conveniente operar a velocidades de dilución pequeñas (D

La enfermedad de Parkinson (EP) es un desorden neurodegenerativo queafecta la coordinación de músculos y extremidades, incluyendo aquellosresponsables de la producción del habla, generando alteraciones en lainteligibilidad de la señal de voz. Está demostrado que el ejercicio terapéuticoconstante puede mejorar las habilidades de comunicación de los pacientes; sinembargo, el diagnóstico acerca del avance en el proceso de recuperación esrealizado de forma subjetiva por los fonoaudiólogos o neurólogos. Debido aesto se requiere el desarrollo de herramientas flexibles que valoren y guíen laterapia fonoaudiológica de los pacientes. En este artículo se presenta el diseñoe implementación de un sistema embebido para el análisis en tiempo real dela voz de pacientes con EP. Para esto se desarrollan tres plataformas; primero,se construye una interfaz gráfica en Matlab; luego, se crea un primer prototipobasado en un DSP TMS320C6713 de Texas Instruments. La aplicación finales desarrollada sobre un mini-ordenador que cuenta con un códec de audio,capacidad de almacenamiento, y una unidad de procesamiento. El sistemaademás se complementa con un monitor LCD para desplegar información entiempo real, y un teclado para la interacción con el usuario.En todas las plataformas se evalúan diferentes medidas usadas comúnmenteen la valoración de la voz de pacientes con EP, incluyendo característicasacústicas y de dinámica no lineal. En concordancia con otros trabajos delestado del arte donde se analiza la voz de personas con EP, la plataformadiseñada muestra un incremento en la variación del pitch en la voz de lospacientes, además de un decremento en el valor del área del espacio vocálico.Este resultado indica que la herramienta diseñada puede ser útil para hacer laevaluación y seguimiento de la terapia fonoaudiológica de pacientes con EP.

We describe a practice designed for the numerical study of the Lorenz model that is a central model in the physics of lasers. The didactical objectives pursued in this practice have a dual nature, considering both the introduction to the knowledge of a physical paradigm of deterministic chaos as the training for the use of certain computational tools for its characterization. The method used to achieve programming is finding solutions of the Lorenz model and systematically studying of their temporal evolution using a Mathematica program. In the academic context, the practice is designed to be included in the curriculum of the degree in physics and to facilitate adaptation to other matters in this area, such as quantum optics, fluids, mechanical vibrations, etc. We first study the steady states and their linear stability, of the Lorenz model equations and then numerically study the different types of dynamic behavior. We pay special attention to the deterministic chaotic behavior and to the sequence of bifurcations leading from periodic to chaotic behavior (routes to chaos). [ABSTRACT FROM AUTHOR]

This article presents a system of three first-orden ordinary differential equations to study the dynamic interaction between renewable resources, population and environmental pollution in a region. The model is achieved coupling a dynamic equation of contamination to formulated systems by Simone D'alessandro and shows that under the Hopf bifurcation can be found conditions to achieve sustainable development under the definition given in the report of Brundtland commission 1987. That is, when a harmonic balance between the state variables of the model is reached. [ABSTRACT FROM AUTHOR]

O presente estudo, de caráter teórico, objetivou analisar e discutir um possível código binário para o sistema de Enfermagem, no sentido de identificar o seu próprio saber, na perspectiva dos pressupostos teóricos de Niklas Luhmann. Apostar em uma comunicação funcionalmente diferenciada e socialmente relevante para o sistema de enfermagem implica em transcender o tradicional código saúde-doença, predominante no sistema de saúde e cuja comunicação socialmente relevante é a doença. Implica, ainda, em investir proativamente na promoção e proteção do viver saudável de indivíduos, famílias e comunidades, para que a saúde seja o ponto central das discussões e intervenções.

This was a qualitative study with the purpose of designing a meta-model for the work process of the Family Health Strategy (FHS) team. It was based on the experience of six sample groups, composed of their members (physicians, professional nurses, dentists, dental assistants, licensed technical nurses and community health agents) in a city in São Paulo state, Brazil, totaling 54 subjects. Six theoretical models emerged from non-directive interviews. These were analyzed according to Grounded Theory and submitted to the meta-synthesis strategy, which produced the meta-model "between the processes of strengthening and weakening of the FHS model: professional-team-community reciprocity as an intervening component". When analyzed in light of the Theory of Complexity (TC), it showed to be a work with a vertical and authoritarian tendency, which is largely hegemonic in the tradition of public health care policies.

FUNDAMENTO: Várias publicações têm demonstrado a importância do sistema nervoso autônomo por meio dos componentes simpático e parassimpático na gerência da interação entre as diferentes partes do organismo humano. Esses estudos aplicaram técnicas lineares e não lineares (Teoria do Caos) de avaliação em diferentes situações, doenças e faixas etárias, tendo como ferramenta a variabilidade da frequência cardíaca (VFC). OBJETIVO: Aplicar os conhecimentos das dinâmicas linear e não linear na avaliação de neonatos prematuros (NPT), analisando sua VFC e comparando com neonatos de termo (NT) saudáveis. MÉTODOS: Quarenta e oito neonatos prematuros com diferentes idades gestacionais tiveram seus batimentos cardíacos captados com auxílio do equipamento Polar Advanced S810i e sua VFC obtida pelo registro dos intervalos RR. A VFC foi analisada nos domínios do tempo (SDNN, RMSSD, SD1/SD2), da frequência (VLF, LF, HF e a relação LF/HF) e do caos (TAU e sua normalização [TAU(n)], Expoente de Lyapunov e Entropia). Os NPT foram comparados com um grupo de 78 NT saudáveis e sem intercorrências perinatais com auxílio do teste não paramétrico de Kruskal-Wallis. RESULTADOS: Detectou-se diferença estatisticamente significante entre os grupos para todas as variáveis estudadas, tanto no domínio do tempo como nos da frequência e do caos. CONCLUSÃO: Neonatos prematuros exibem comportamento menos complexo da variabilidade da frequência cardíaca que neonatos de termo, fato comprovado nos domínios do tempo, da frequência e do caos. O estudo da variabilidade cardíaca nesse grupo pode ser considerado uma ferramenta a mais na avaliação da maturação autonômica e, consequentemente, da progressão para eutrofia.FUNDAMENTO: Varias publicaciones han demostrado la importancia del sistema nervioso autónomo por medio de los componentes simpático y parasimpático en el manejo de la interacción entre las diferentes partes del organismo humano. Esos estudios aplicaron técnicas lineales y no lineales (Teoría del Caos) de evaluación en diferentes situaciones, enfermedades y franjas etáreas, teniendo como herramienta la variabilidad de la frecuencia cardíaca (VFC). OBJETIVO: Aplicar los conocimientos de las dinámicas lineal y no lineal en la evaluación de neonatos prematuros (NPT), analizando su VFC y comparándola con neonatos de término (NT) sanos. MÉTODOS: Cuarenta y ocho neonatos prematuros con diferentes edades gestacionales tuvieron captados sus latidos cardíacos con auxilio del equipamiento Polar Advanced S810i y su VFC obtenida por el registro de los intervalos RR. La VFC fue analizada en los dominios del tiempo (SDNN, RMSSD, SD1/SD2), de la frecuencia (VLF, LF, HF y la relación LF/HF) y del caos (TAU y su normalización [TAU(n)], Exponente de Lyapunov y Entropía). Los NPT fueron comparados con un grupo de 78 NT sanos y sin intercurrencias perinatales con auxilio del test no paramétrico de Kruskal-Wallis. RESULTADOS: Se detectó diferencia estadísticamente significativa entre los grupos para todas las variables estudiadas, tanto en el dominio del tiempo como en los de la frecuencia y del caos. CONCLUSIÓN: Neonatos prematuros exhiben comportamiento menos complejo de la variabilidad de la frecuencia cardíaca que neonatos de término, hecho comprobado en los dominios del tiempo, de la frecuencia y del caos. El estudio de la variabilidad cardíaca en ese grupo puede ser considerado una herramienta más en la evaluación de la maduración autonómica y, consecuentemente, de la progresión a eutrofia.BACKGROUND: Several studies have demonstrated the importance of the autonomic nervous system through sympathetic and parasympathetic components in the management of the interaction between different parts of the body. These studies have applied linear and nonlinear techniques (Chaos Theory) for assessment in different situations, illnesses and age groups, using the heart rate variability (HRV). OBJECTIVE: To apply knowledge of linear and nonlinear dynamics in the assessment of preterm neonates (PTN), analyzing their HRV and comparing with healthy term neonates (NT). METHODS: Forty-eight premature neonates with different gestational ages had their heart rates assessed with the aid of a Polar Advanced S810i and HRV obtained by recording RR intervals. HRV was analyzed according to time (SDNN, RMSSD, SD1/SD2), frequency (VLF, LF, HF and LF/HF) and chaos (TAU and its standardization [TAU(n)], Lyapunov Exponent and Enthropy). PTN were compared with a group of 78 healthy NT with no perinatal events using Kruskal-Wallis nonparametric test. RESULTS: We detected a statistically significant difference between groups for all variables, both in time, frequency and chaos. CONCLUSION: Preterm Neonates have a less complex heart rate variability behavior than term neonates, which was evident in time, frequency and chaos. The study of heart rate variability in this group can be considered another tool in the evaluation of autonomic maturation and hence the progression to normality.

FUNDAMENTO: O tabagismo altera a função autonômica. OBJETIVO: Investigar os efeitos agudos do tabagismo sobre a modulação autonômica e a recuperação dos índices de variabilidade de frequência cardíaca (VFC) pós-fumo, por meio do plot de Poincaré e índices lineares. MÉTODOS: Foram avaliados 25 fumantes jovens, os quais tiveram a frequência cardíaca analisada, batimento a batimento, na posição sentada, após 8 horas de abstinência, por 30 minutos em repouso, 20 minutos durante o fumo e 30 minutos pós-fumo. Análise de variância para medidas repetidas, seguido do teste de Tukey, ou teste de Friedman seguido do teste de Dunn foram aplicados dependendo da normalidade dos dados, com p < 0,05. RESULTADOS: Durante o fumo, houve redução dos índices SD1 (23,4 ± 9,2 vs 13,8 ± 4,8), razão SD1/SD2 (0,31 ± 0,08 vs 0,2 ± 0,04), RMSSD (32,7 ± 13 vs 19,1 ± 6,8), SDNN (47,6 ± 14,8 vs 35,5 ± 8,4), HFnu (32,5 ± 11,6 vs 19 ± 8,1) e do intervalo RR (816,8 ± 89 vs 696,5 ± 76,3) em relação ao repouso, enquanto que aumentos do índice LFnu (67,5 ± 11,6 vs 81 ± 8,1) e da razão LF/HF (2,6 ± 1,7 vs 5,4 ± 3,1) foram observados. A análise visual do plot mostrou menor dispersão dos intervalos RR durante o fumo. Com exceção da razão SD1/SD2, os demais índices apresentaram recuperação dos valores, 30 minutos após o tabagismo. CONCLUSÃO: O tabagismo produziu agudamente modificações no controle autonômico, caracterizadas por ativação simpática e retirada vagal, com recuperação 30 minutos após o fumo.FUNDAMENTO: El tabaquismo altera la función autonómica. OBJETIVO: Investigar los efectos agudos del tabaquismo sobre la modulación autonómica y la recuperación de los índices de variabilidad de frecuencia cardíaca (VFC) post tabaco, por medio del plot de Poincaré e índices lineales. MÉTODOS: Fueron evaluados 25 fumantes jóvenes, los cuales tuvieron la frecuencia cardíaca analizada, latido a latido, en la posición sentada, después de 8 horas de abstinencia, por 30 minutos en reposo, 20 minutos durante el tabaco y 30 minutos post tabaco. Análisis de varianza para medidas repetidas, seguido del test de Tukey, o test de Friedman seguido del test de Dunn fueron aplicados dependiendo de la normalidad de los datos, con p < 0,05. RESULTADOS:: Durante el tabaco, hubo reducción de los índices SD1 (23,4 ± 9,2 vs 13,8 ± 4,8), razón SD1/SD2 (0,31 ± 0,08 vs 0,2 ± 0,04), RMSSD (32,7 ± 13 vs 19,1 ± 6,8), SDNN (47,6 ± 14,8 vs 35,5 ± 8,4), HFnu (32,5 ± 11,6 vs 19 ± 8,1) y del intervalo RR (816,8 ± 89 vs 696,5 ± 76,3) en relación al reposo, mientras que aumentos del índice LFnu (67,5 ± 11,6 vs 81 ± 8,1) y de la razón LF/HF (2,6 ± 1,7 vs 5,4 ± 3,1) fueron observados. El análisis visual del plot mostró menor dispersión de los intervalos RR durante el tabaco. Con excepción de la razón SD1/SD2, los demás índices presentaron recuperación de los valores, 30 minutos después del tabaquismo. CONCLUSIÓN: El tabaquismo produjo agudamente modificaciones en el control autonómico, caracterizadas por activación simpática y retirada vagal, con recuperación 30 minutos después del tabaco.BACKGROUND: Smoking affects the autonomic function. OBJECTIVE:To investigate the acute effects of smoking on the autonomic modulation and the post-smoking recovery of the heart rate variability (HRV) index through Poincare plot and linear indices. METHODS: A total of 25 young smokers underwent beat-to-beat analysis of heart rate in the sitting position after 8 hours of tobacco abstinence, for 30 minutes at rest, 20 minutes while smoking and 30 minutes after smoking. The analysis of variance for repeated measures, followed by Tukey's test or Friedman's test followed by Dunn's test, were applied depending on the normality of data, with p < 0.05. RESULTS: While smoking, there was a decrease in the indices: SD1 (23.4 ± 9.2 vs 13.8 ± 4.8), SD1/SD2 ratio (0.31 ± 0.08 vs 0.2 ± 0.04), RMSSD (32,7 ± 13 vs 19.1 ± 6.8), SDNN (47.6 ± 14.8 vs 35.5 ± 8.4), HFnu (32,5 ± 11.6 vs 19 ± 8.1) and the RR interval (816.8 ± 89 vs 696.5 ± 76.3) in relation to the rest period, whereas increases in the LFnu index (67.5 ± 11.6 vs 81 ± 8.1) and the LF/HF ratio (2.6 ± 1.7 vs 5.4 ± 3.1) were observed. The visual analysis of the plot showed a lower dispersion of RR intervals while smoking. Except for the SD1/SD2 ratio, the other indices presented recovery of values 30 minutes after smoking. CONCLUSION: Smoking resulted in acute modifications of the autonomic control, characterized by sympathetic activation and vagal withdrawal, presenting recovery 30 minutes after smoking.

Se indica cómo manejar una gran base de datos consistente de series temporales no lineales, aplicando distintas técnicas de modelamiento no lineal a estas series. Aunque no existen guías explícitas de manipulación de series temporales no lineales en la profusa bibliografía actual, existen diferentes enfoques que pueden ser tomados en cuenta. Para ello se estudió una base de datos mensual correspondiente a datos del Fenómeno del Niño (ENSO), entre los años 1866 y 2006. Se explica cómo debe manipularse esta base de datos que poseen características de no linealidad, la cual será usada para hacer pronósticos varios pasos en adelante. Se aplicaron dos test estándar: Información Mutua Promedio (AMI) y Falsos Vecinos más Cercanos (FNN). Se obtuvo el espaciamiento óptimo de los datos, así como el número de datos hacia atrás necesarios para pronosticar valores hacia el futuro. Luego, se diseñaron varios modelos de redes neuronales artificiales (RNA), con diferentes reglas de aprendizajes, funciones de transferencia, elementos de procesamiento (o neuronas) en la capa escondida, etc., que permitieron hacer pronóstico de hasta 20 pasos en adelante. Las mejores redes correspondieron a aquellas que poseían como regla de aprendizaje la Regla Delta y la Regla Extendida, con función de transferencia sigmoide y tangente hiperbólica. El tipo de RNA usada fue una de multicapas alimentada hacia adelante y entrenada mediante la técnica de propagación hacia atrás. Se probaron redes con una, dos capas ocultas y sin ninguna capa. El mejor modelo que se obtuvo resultó ser uno consistente de una capa oculta.We indicate how to handle a large database consisting of nonlinear time series, applying different nonlinear modelling techniques to this kind of times series. Nowadays in the current references there is no explicit guide of how to manipulate data from nonlinear time series; however, there are approaches that can be taken account. To this end we studied a monthly database corresponding to South Oscillation Index (SOI) and between the years 1886 to 2006. It explains how there must manipulated this database whose data possess nonlinear characteristic, which will be used to do forecasts several steps ahead. Two standard tests to this database were applied, the Average Mutual Information (AMI) and the False Nearest Neighbours (FNN). The optimal spacing of the information was obtained as well as the number of values backward necessary to predict values towards the future. Then, several models were designed of artificial neural nets (ANN), with different learning rules, function of transfer, elements of process (or neurons) in the hidden layer, etc., that allowed to do forecasting of up to 20 steps ahead. The best networks were those that possessed the rules of learning called extDBD and Delta-Rule, and sigmoid as well as hyperbolic tangent as function of transfer. The type of used network was one of feedforward multilayer perceptron and trained by means of backpropagation technique. Networks were proved by one, two hidden layers and without any hidden layer. The best model that was obtained it turned out to be one that consisted with an alone hidden layer.

In order to characterize physiological signals, which may have highly nonlinear structures, it’s common to use methodologies derived from fractal techniques that make part of complexity analysis. This work proposes is proposed an evaluation function based on measuring the capacity of prediction of a neural network trained with Kalman filter to predict points in a reconstructed state space attractor, so measuring the quality of the attractor from a onedimensional signal. We propose use of statistic measures such as Kullback –Leibler, Kolmogorov-Smirnov and Hellinger to determine difference between the embedded statistic structure in the predicted points and the original signal points. Results were obtained on attractor reconstruction from ECG signals of MIT-BIH database and EEG signals obtained from Clinic for Epileptologie Epileptologie Bonn University database. In this way, it was possible to evaluate the prediction capacity corresponding to reconstruct attractors from records, from which we concluded that an attractor with high capacity of time series prediction implies good embedding properties in state space.

Se diseñó una red neuronal artificial (RNA) para hacer predicciones de valores de concentraciones horarias de material particulado fino en la atmósfera. El estudio está basado en los datos de tres años de series de tiempo de pm2.5 (material particulado suspendido de 2,5 micrones de diámetro), obtenidos en una estación céntrica de la Red MACAM de la ciudad de Santiago de Chile, entre los años 1994 y 1996. Para obtener el espaciamiento óptimo de los datos, así como el número de datos hacia atrás necesarios para pronosticar el valor futuro, se aplicaron dos test estándar usados en estudio de sistemas dinámicos, como Información Mutua promedio (AMI) y Falsos Vecinos más Cercanos (FNN). De esta manera se encontró que lo más conveniente era considerar como entrada los datos de PM2.5 cada seis horas durante un día (cuatro datos), y en base a ellos predecir el dato siguiente. Una vez fijo el número de variables de entrada y elegida la variable a pronosticar, se diseñó un modelo predictivo basado en la técnica de RNA. El tipo de modelo de RNA usado fue uno de multicapas, alimentado hacia adelante y entrenado mediante la técnica de propagación hacia atrás. Se probaron redes sin capa oculta y con una y dos capas ocultas. El mejor modelo resultó ser con una capa oculta, a diferencia de lo obtenido en trabajo anterior que reportaba que la red sin capa oculta era más eficiente. Los resultados fueron más precisos que los obtenidos con un modelo de persistencia (el valor en seis horas más será el mismo que el actual).An artificial neural network for the forecasting of concentrations of fine particulate matter in the atmosphere was designed. The data set analyzed corresponds to three years of pm2.5 time series (particulate matter in suspension with aerodynamic diameter less than 2,5 microns), measured in a station that belongs to Santiago's monitoring network (Red MACAM) and is located near downtown. We consider measurements of concentrations between May and August for years between 1994 and 1996. In order to find the optimal time spacing between data and the number of values into the past necessary to forecast a future value, two standard tests were performed, Average Mutual Information (AMI) and False Nearest Neighbours (FNN). The results of these tests suggest that the most convenient choice for modelling was to use 4 data with 6 hour spacing on a given day as input in order to forecast the value at 6 AM on the following day. Once the number and type of input and output variables are fixed, we implemented a forecasting model based on the neural network technique. We used a feedforward multilayer neural network and we trained it with the backpropagation algorithm. We tested networks with none, one and two hidden layers. The best model was one with one hidden layer, in contradiction with a previous study that found that minimum error was obtained with a net without hidden layer. Forecasts with the neural network are more accurate than those produced with a persistence model (the value six hours ahead is the same as the actual value).

This paper presents a system for the automatic detection of hypernasal speech signals based on the combination of two different characterization approaches applied to the five spanish vowels and two selected words. The first approach is based on classical features such as pitch period perturbations, noise measures, and Mel-Frequency Cepstral Coefficients (MFCC). The second approach is based on the Non-Linear Dynamics (NLD) analysis. The most relevant features are selected and sorted using two techniques: Principal Components Analysis (PCA) and Sequential Forward Floating Selection (SFFS). The decision about whether a voice record is hypernasal or healthy is taken using a Soft Margin - Support Vector Machine (SM-SVM). Experiments upon recordings of the five Spanish vowels and the words /coco/ and /gato/, are performed considering three different set of features: (1) the classical approach, (2) the NLD analysis, and (3) the combination of the classical and NLD measures. In general, the accuracies are higher and more stable when the classical and NLD features are combined, indicating that the NLD analysis is complementary to the classical approach. [ABSTRACT FROM AUTHOR]

Comúnmente los autores de literatura sobre Caos reportan un solo evento caótico truncado que acontece en los sistemas caóticos que ellos han investigado. Este documento reporta múltiples eventos caóticos detectados en el oscilador no lineal amortiguado y forzado. Con la finalidad de detectar Caos en este oscilador, el autor de este reporte desarrolló un Laboratorio Virtual (software interactivo e integrado), con el cual se ejecutaron muchas simulaciones y también se extrajeron y compararon Mapas de Poincaré para ángulos de 0° y 180°, a fin de evitar duplicidad de eventos. Se encontró que los eventos caóticos no son imperecederos, ellos tienen un inicio y un final, lo cual significa que ellos son transitorios. Tampoco se detectó relación numérica alguna entre los valores de la frecuencia natural del oscilador caótico con aquella de la fuerza periódica aplicada.

Study behaviors displayed by teams of students in learning processes with the centroid determination which explains the connectivity between team members. Proving that evolution, over time, the emotional field influence other dimensionalities nonlinear model applied and the quality of learning. [ABSTRACT FROM AUTHOR]

El objetivo del presente trabajo es exponer y evaluar la hipótesis del crecimiento cíclico de Richard Goodwin. Se utilizan datos colombianos para contrastar los supuestos del modelo. Se encontró que a nivel cualitativo, la dinámica de las variables de estado en el espacio de fases muestra cierta correspondencia con las predicciones teóricas, al menos para dos períodos: 1957-1966 y 1968-1974. Los resultados cuantitativos rechazan los supuestos del modelo y los modelos empíricos no describen el verdadero proceso generador de los datos.

The trend of the indexes of the nonlinear dynamics in an environmental pre-contingency by particles PM10 in the Metropolitan Area of Mexico Valley was found. The tools of chaos theory were applied to determine the dynamic behavior coincidences and the study period from December 15 to January 7 was selected. The indexes of nonlinear dynamics were calculated to evaluate the changes in the dynamic behavior and the attractors in the phase space were plotted. The results obtained in terms of persistence, divergence and autocorrelation vary depending on the concentration of PM10. The Hurst exponent allowed finding the best concordance with PM10 and it was observed that when it exceeds the value of 0.3 the probability of reaching a pre-contingency event increases. [ABSTRACT FROM AUTHOR]

Improving accuracy in the diagnosis and prognosis of industrial maintenance has been a constant task of research to preserve the continuous operation of machines. Today is necessary to improve this technique for avoiding reductionism that the traditional linear techniques employ. In this paper it is studied the centrifugal pump cavitation state. To simulate the phenomenon, a test bed is constructed and the fluid is blocked toward the impeller of pump by the suction valve, the time signals were recorded using an accelerometer. Subsequently, a chaotic nonlinear study was used to represent the geometry in the phase space and validation was performed with the data recording operation of the centrifugal pump without cavitation and with maximum efficiency. The results showed that the system dynamics is non-linear and chaotic, and the cavitation is represented with a characteristic geometry. [ABSTRACT FROM AUTHOR]

This study aims to present a theoretical reflection that enables to expand nursing care as a complex phenomenon, in which and for which, frequently, are not have linear and predictable answers. Signal up aspects that drive the need to adopt new models of thought, capable of admit the adverse and contradictory processes in everyday life of being and doing nursing. It discusses, need to overcome the logic of fragmentation, of predictability, of certainty and of the excessive order - ready recipes of care - still outstanding in care practices. [ABSTRACT FROM AUTHOR]

Investigaciones recientes sobre la naturaleza de los sistemas no lineales complejos permiten proponer un punto de vista alternativo de la evolución, en el que se enfatiza la necesidad de un cambio radical en la concepción dominante de causalidad. En esta nueva perspectiva, la autoorganización, la dinámica de bifurcaciones y la evolución caótica se convierten en conceptos claves en la evolución de los sistemas socio-naturales. Las consecuencias de estas ideas para el discurso histórico son profundas puesto que implican una reconsideración de la relación entre contingencia y determinismo. En este artículo se propone que la integración de estos conceptos en un nuevo modelo de práctica arqueológica es un desafío esencial para el futuro de la disciplina.

Parkinson’s disease (PD) is a neurodegenerative disorder that affects the coordination of muscles and limbs, including those responsible of the speech production. The lack of control of the limbs and muscles involved in the speech production process can generate intelligibility problems and this situation has a negative impact in the social interaction of the patients. It is already demonstrated that constant speech therapy can improve the communication abilities of the patients; however, the measurement of the recovery progress is done subjectively by speech therapists and neurologists. Due to this, it is required the development of flexible tools able to asses and guide the speech therapy of the patients. In this paper the design and deployment of a new device for the real time assessment of speech signals of people with PD is presented. The processes of design and deployment include the development on three platforms: first, a graphic user interface is developed on Matlab, second the first prototype is implemented on a digital signal processor (DSP) and third, the final device is developed on a mini-computer. The device is equipped with an audio codec, storage capacity and the processing unit. Besides, the system is complemented with a monitor to display the processed information on real time and with a keyboard enabling the interaction of the end-user with the device. Different acoustics and nonlinear dynamics measures which have been used in the state of the art for the assessment of speech of people with PD are implemented on the three mentioned platforms. In accordance with the state of the art, the designed platforms show an increment in the variation of the fundamental period of speech (commonly called pitch) of people with PD. Additionally, the decrease of the vocal space area is validated for the case of patients with PD. These results indicate that the designed device is useful to perform the assessment and monitoring of the speech therapy of people with PD. [ABSTRACT FROM AUTHOR]

Copyright of Revista Sul-Americana de Engenharia Estrutural is the property of Revista Sul-Americana de Engenharia Estrutural and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Discusiones Filosóficas is the property of Universidad de Caldas and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Andaluza de Medicina del Deporte is the property of Centro Andaluza de Medicina del Deporte and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Intention has a well-recognised role in the termination point of fatigue-induced exercise; however its interaction with physiological factors is unknown. The linear causal model applied to mind-body relationships does not explain several characteristic phenomena related to the termination point in tasks defined by motor intention. This paper aims to investigate the role of intention in terminating exercise and reveal the non-linear psychobiological integration that occurs during fatiguing efforts. On the basis of the experimental results, we conclude that the mechanism responsible for termination is the dissolution of the intentional attractor that is produced by the growing instability that fatigue produces in the neuromuscular axis. These findings point to the existence of a non-linear, dynamic psychobiological integration in exercise-induced fatigue. [ABSTRACT FROM AUTHOR]

We indicate how to handle a large database consisting of nonlinear time series, applying different nonlinear modelling techniques to this kind of times series. Nowadays in the current references there is no explicit guide of how to manipulate data from nonlinear time series; however, there are approaches that can be taken account. To this end we studied a monthly database corresponding to South Oscillation Index (SOI) and between the years 1866 to 2006. It explains how there must manipulated this database whose data possess nonlinear characteristic, which will be used to do forecasts several steps ahead. Two standard tests to this database were applied, the Average Mutual Information (AMI) and the False Nearest Neighbours (FNN). The optimal spacing of the information was obtained as well as the number of values backward necessary to predict values towards the future. Then, several models were designed of artificial neural nets (ANN), with different learning rules, function of transfer, elements of process (or neurons) in the hidden layer, etc., that allowed to do forecasting of up to 20 steps ahead. The best networks were those that possessed the rules of learning called extDBD and Delta-Rule, and sigmoid as well as hyperbolic tangent as function of transfer. The type of used network was one of feedforward multilayer perceptron and trained by means of backpropagation technique. Networks were proved by one, two hidden layers and without any hidden layer. The best model that was obtained it turned out to be one that consisted with an alone hidden layer. [ABSTRACT FROM AUTHOR]

Copyright of Revista Criterio Libre is the property of Revista Criterio Libre and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this work we present a comparison between different integration algorithms and different initial conditions in a simulation of a granular material by using Molecular Dynamics. The different global error of each integration method implies that final results, as system configurations and total energy, will depend on the employed integration algorithm and on the time step. Moreover, the initial conditions play an important role in granular materials due to the high sensibilty to them, since granular materials have strong non-linear micromechanical interacctions. We present a practical example that shows some different final results for different initial conditions and different integration algorithms in the simulation of a granular material on three dimensions. This behaviour should be taken into account in all kind of time driven molecular dynamics simulations, and not only in granular material simulations. [ABSTRACT FROM AUTHOR]

The article presents an analysis of time series with different heart rate with analysis computational of chaos and nonlinear dynamics theory. The authors aim to know the complexity of system and find visual recognize patterns. They found that cardiac cycle is a mixed dynamic behavior system and the representations in space phase obtained from the relation between the original signal and first derived.

An artificial neural network for the forecasting of concentrations of fine particulate matter in the atmosphere was designed. The data set analyzed corresponds to three years of pm2.5 time series (particulate matter in suspension with aerodynamic diameter less than 2, 5 microns), measured in a station that belongs to Santiago's monitoring network (Red MACAM) and is located near downtown. We consider measurements of concentrations between May and August for years between 1994 and 1996. In order to find the optimal time spacing between data and the number of values into the past necessary to forecast a future value, two standard tests were performed, Average Mutual Information (AMI) and False Nearest Neighbours (FNN). The results of these tests suggest that the most convenient choice for modelling was to use 4 data with 6 hour spacing on a given day as input in order to forecast the value at 6 AM on the following day. Once the number and type of input and output variables are fixed, we implemented a forecasting model based on the neural network technique. We used a feedforward multilayer neural network and we trained it with the backpropagation algorithm. We tested networks with none, one and two hidden layers. The best model was one with one hidden layer, in contradiction with a previous study that found that minimum error was obtained with a net without hidden layer. Forecasts with the neural network are more accurate than those produced with a persistence model (the value six hours ahead is the same as the actual value). [ABSTRACT FROM AUTHOR]