Study of nonlinear viscoelastic mechanical properties of degenerated intervertebral discs / Estudio de las propiedades mecánicas viscoelásticas no lineales de discos intervertebrales degenerados

SUMMARY: Biomechanical factors are important factors in inducing intervertebral disc degeneration, in this paper, the nonlinear viscoelastic mechanical properties of degenerated intervertebral discs were analyzed experimentally. Firstly, the loading and unloading curves of intervertebral discs before and after degeneration at different strain rates were compared to analyze the changes of their apparent viscoelastic mechanical properties; The internal stress/strain distribution of the disc before and after degeneration was then tested by combining digital image technology and fiber grating technology. The results show that the intervertebral disc is strain-rate- dependent whether before or after degeneration; The modulus of elasticity and peak stress of the degenerated disc are significantly reduced, with the modulus of elasticity dropping to 50 % of the normal value and the peak stress decreasing by about 55 %; Degeneration will not change the distribution of the overall internal displacement of the intervertebral disc, but has a greater impact on the superficial and middle AF; The stress in the center of the nucleus pulposus decreases, and the stress in the outer AF increases after degeneration. Degeneration has a great impact on the nonlinear viscoelastic mechanical properties of intervertebral disc, which has reference value for the mechanism, treatment and prevention of clinical degenerative diseases.

RESUMEN: Los factores biomecánicos son importantes en la inducción de la degeneración del disco intervertebral. En este estudio se analizaron experimentalmente las propiedades mecánicas viscoelásticas no lineales de los discos intervertebrales degenerados. En primer lugar se compararon las curvas de carga y descarga de los discos intervertebrales, antes y después de la degeneración, a diferentes velocidades de deformación para analizar los cambios aparentes de sus propiedades mecánicas viscoelásticas. La distribución interna de tensión/deformación del disco antes y después de la degeneración se probó luego combinando tecnología de imagen digital y tecnología de rejilla de fibra. Los resultados mostraron que el disco intervertebral depende de la velocidad de deformación antes o después de la degeneración; El módulo de elasticidad y la tensión máxima del disco degenerado se reducen significativamente, cayendo el módulo de elasticidad al 50 % del valor normal y la tensión máxima disminuyendo en aproximadamente un 55 %; La degeneración no cambiará la distribución del desplazamiento interno general del disco intervertebral, pero tiene un mayor impacto en la FA superficial y media; El estrés en el centro del núcleo pulposo disminuye y el estrés en el FA externo aumenta después de la degeneración. La degeneración tiene un gran impacto en las propiedades mecánicas viscoelásticas no lineales del disco intervertebral, que tiene valor de referencia para el mecanismo, tratamiento y prevención de enfermedades clínicas degenerativas.

Reflections on the fundamental nature of homeopathic potencies: Plasma, Langmuir Adsorption and Vitalism

There is a pressing need to develop methods and approaches that will identify the fundamental nature of homeopathic potencies. Aims: To bring together recent basic research on potencies, especially that using solvatochromic dyes, and to supplement these results with reliable observations made by Hahnemann and his contemporaries from the very beginnings of homeopathy, together with a detailed examination of the process of trituration and succussion coupled to dilution, in order to significantly limit the number of possible explanations as to the identity of potencies. Methodology: A mixture of lab based and literature studies such that as far as possible all verified and substantiated observations about homeopathic potencies have been examined. Results and Discussion: An understanding of the fundamental nature of homeopathic potencies that includes all known and accepted observations (in vitro, in vivoand clinical) is not realistic without embracing hypotheses involving the emergent properties of complex systems and in particular, vitalistic concepts. Using a vitalistic model it is possible to explain a wide range of seemingly unrelated phenomena -such as the polarising effect of potencies on solvatochromic dyes, the ability to use a range of materials such as water, lactose and cellulose as carriers of potencies, the administering of potencies by olfaction, the antidoting effect of camphor on potency action, the non-linear dependence of potency strength on volume as well as succussion level, the oscillatory behaviour of potencies and experimenter/observer/practitioner effects. Conclusion: A hypothesis in which homeopathic potencies can be seen as self-actuating and autonomous plasma generated by trituration and/or succussion and carried according to Langmuir adsorption models fits the known observations about potencies.

Research progress and application of transfer entropy algorithm / 生物医学工程学杂志

In recent years, exploring the physiological and pathological mechanisms of brain functional integration from the neural network level has become one of the focuses of neuroscience research. Due to the non-stationary and nonlinear characteristics of neural signals, its linear characteristics are not sufficient to fully explain the potential neurophysiological activity mechanism in the implementation of complex brain functions. In order to overcome the limitation that the linear algorithm cannot effectively analyze the nonlinear characteristics of signals, researchers proposed the transfer entropy (TE) algorithm. In recent years, with the introduction of the concept of brain functional network, TE has been continuously optimized as a powerful tool for nonlinear time series multivariate analysis. This paper first introduces the principle of TE algorithm and the research progress of related improved algorithms, discusses and compares their respective characteristics, and then summarizes the application of TE algorithm in the field of electrophysiological signal analysis. Finally, combined with the research progress in recent years, the existing problems of TE are discussed, and the future development direction is prospected.

Nursing care as a systemic and entrepreneurial phenomenon / El cuidado de enfermería como fenómeno sistémico y emprendedor / O cuidado de enfermagem como fenômeno sistêmico e empreendedor

ABSTRACT The objective is to produce a critical-reflexivity analysis of nursing care, from the perspective of complexity thinking and social entrepreneurship. Theoretical-reflective study, supported by the framework of complexity thinking and social entrepreneurship. The main characteristics that lead and support nursing care are analyzed from a systemic-entrepreneurial perspective. A parallel is conceived between vertical care, design from a hierarchical structure and nursing care in the systemic-entrepreneurial perspective, which leads to singularity, originality, circularity, complementarity and interactivity. The centrality of nursing care is reaffirmed as a tangible social good or not. Theoretical reflection on nursing care as a systemic and entrepreneurial phenomenon raises a unique and multidimensional perception of the human being/user, health, the nursing work process, in order to achieve an increasingly agile, dynamic, circular, complementary and interdependent care.

RESUMEN Este estudio pretende realizar un análisis crítico-reflexivo de los cuidados de enfermería desde la perspectiva del pensamiento de la complejidad y del emprendimiento social. Se trata de un estudio teórico-reflexivo, apoyado en el marco del pensamiento de la complejidad y del emprendimiento social. Se analizan las principales características que conducen y sostienen los cuidados de enfermería desde una perspectiva sistémico-emprendedora. Se establece un paralelismo entre los cuidados verticales, perfilados desde una estructura jerárquica, y los cuidados de enfermería, desde una perspectiva sistémico-emprendedora, que conduce a la singularidad, la originalidad, la circularidad, la complementariedad y la interactividad. Se reafirma la centralidad de los cuidados de enfermería como bien social tangible o intangible. La reflexión teórica sobre el cuidado enfermero como fenómeno sistémico y emprendedor plantea una percepción singular y multidimensional del ser humano/usuario, de la salud y del proceso de trabajo enfermero, para lograr un cuidado cada vez más ágil, dinámico, circular, complementario e interdependiente.

RESUMO Objetiva-se produzir análise crítico-reflexiva sobre o cuidado de enfermagem, na perspectiva teórico-reflexiva do pensamento da complexidade e do empreendedorismo social. Observa-se as principais características que conduzem e sustentam o cuidado de enfermagem na perspectiva sistêmico-empreendedora. Concebe-se um paralelo entre o cuidado vertical, esboçado a partir de uma estrutura hierárquica, e o cuidado de enfermagem na perspectiva sistêmico-empreendedora, que conduz à singularidade, à originalidade, à circularidade, à complementaridade e à interatividade. Reafirma-se a centralidade do cuidado de enfermagem como bem-social tangível ou não. A reflexão teórica acerca do cuidado de enfermagem como fenômeno sistêmico e empreendedor suscita uma percepção singular e multidimensional de ser humano/usuário, saúde, processo de trabalho da enfermagem, no intuito de alcançar um cuidado cada vez mais ágil, dinâmico, circular, complementar e interdependente.

Leadership in Nursing and Health Care in the Light of Complexity Thinking / Liderazgo de Enfermería y salud a la luz del pensamiento de la complejidad / Liderança em Enfermagem e saúde à luz do pensamento da complexidade

ABSTRACT This study aims to perform a critical-reflective analysis of leadership in nursing and health in the light of complexity thinking. This is a theoretical-reflexive essay based on the framework of complexity thinking. A parallel is conceived between traditional Cartesian leadership, outlined from a defined linear hierarchical structure, and leadership from a systemic-complex perspective. A schematic structure is demonstrated between the pyramidal conception and systemic-complex leadership, leading to circularity, complementarity, interdependence, and interactivity. Leadership's central role in nursing and health care is reaffirmed based on interactive, dialogic, and interdependent movements. The theoretical reflection calls for evolutionary and shared leadership in nursing and health, determined by the quality of interactions between members and different systems, in order to respond to the complexity of health phenomena quickly, effectively, and sustainably.

RESUMEN El objetivo es realizar un análisis crítico-reflexivo del liderazgo de enfermería y salud a la luz del pensamiento de la complejidad. Este es un ensayo teórico-reflexivo basado en el referencial del pensamiento de la complejidad. Se establece un paralelismo entre el liderazgo tradicional cartesiano, esbozado desde una estructura jerárquica lineal definida y el liderazgo, desde una perspectiva sistémica-compleja. Se demuestra una estructura esquemática entre la concepción piramidal y el liderazgo sistémico-complejo que conduce a la circularidad, la complementariedad, la interdependencia y la interactividad. Se reafirma el papel central del liderazgo en la enfermería y la salud, desde movimientos interactivos, dialógicos e interdependientes. La reflexión teórica reclama un liderazgo evolutivo y compartido en la enfermería y la salud, determinado por la calidad de las interacciones entre los miembros y los diferentes sistemas para responder a la complejidad de los fenómenos sanitarios de forma rápida, eficaz y sostenible.

RESUMO Objetiva-se realizar análise crítico-reflexiva sobre a liderança em enfermagem e saúde, à luz do pensamento da complexidade. Ensaio teórico-reflexivo alicerçado no referencial do pensamento da complexidade. Concebe-se um paralelo entre a liderança tradicional cartesiana, esboçada a partir de uma estrutura hierárquica linear definida e a liderança na perspectiva sistêmico-complexa. Demonstra-se uma estrutura esquemática entre a concepção piramidal e a liderança sistêmico-complexa que conduz à circularidade, complementaridade, interdependência e interatividade. Reafirma-se o papel central da liderança em enfermagem e saúde, a partir de movimentos interativos, dialógicos e interdependentes. A reflexão teórica convoca à liderança evolutiva e compartilhada em enfermagem e saúde, determinada pela qualidade das interações entre os membros e os diferentes sistemas, no sentido de responder à complexidade dos fenômenos de saúde de forma rápida, eficaz e sustentável.

Cultura del caos / Chaos Culture

La Teoría del Caos, considerada la tercera revolución de la física, se ha convertido en un método científico para abordar sistemas complejos que no pueden ser explicados por los recursos tradicionales de la ciencia. Su campo de aplicación es cada vez más amplio, porque el pensamiento complejo ha ofrecido solución a numerosos sistemas en la naturaleza, la biología y muy diversas esferas de la vida. El objetivo de este trabajo es ofrecer una panorámica general sobre el tema, desde una postura no estrictamente matemática. Se realizó una revisión en la literatura y se expone el conocimiento sedimentado en el tiempo, por los estudiosos y expertos en la materia. Se ofrece una visión general de la Teoría del Caos, las condiciones para su surgimiento, así como sus aspectos y propiedades generales expresadas en sus dos dimensiones: tiempo (sistemas dinámicos) y espacio (fractales). Se hacen explícitos en cada caso, los conceptos y definiciones necesarias para entender y hablar de Caos. En un segundo artículo se expondrán las principales aplicaciones de esta teoría en la medicina y en particular en el campo de las neurociencias. Para los profesionales del sector salud, resulta un reto necesario familiarizarse con este nuevo enfoque, entender su esencia, principios y conceptos, para adquirir una cultura del Caos(AU)

Chaos Theory, considered the third revolution in physics, has become a scientific method to address complex systems that cannot be explained by the traditional resources of science. Its field of application is increasingly wide, because complex thinking has offered solutions to numerous systems in nature, biology and very diverse spheres of life. The objective of this work is to offer a general overview of the subject, from a non-strictly mathematical position. A literature review was carried out and the knowledge settled over time, by scholars and experts in the field, is exposed. An overview of Chaos Theory is offered, the conditions for its emergence, as well as its aspects and general properties expressed in its two dimensions: time (dynamic systems) and space (fractals). The concepts and definitions necessary to understand and speak of Chaos are made explicit in each case. In a second article, the main applications of this theory in medicine and in particular in the field of neurosciences will be exposed. For professionals in the health sector, it is a necessary challenge to become familiar with this new approach, understand its essence, principles and concepts, to acquire a culture of Chaos(AU)

Dinámica no lineal de la regulación autonómica cardiovascular durante la prueba del peso sostenido en pacientes con diabetes mellitus tipo 2 / Nonlinear dynamics of cardiovascular autonomic regulation during the sustained weight test in patients with type 2 diabetes mellitus

Resumen Introducción: La dinámica no lineal de la regulación autonómica cardiovascular a partir de la variabilidad de la frecuencia cardiaca no ha sido previamente estudiada en pacientes con diabetes mellitus tipo 2 mediante la prueba del peso sostenido como inductor de hiperreactividad cardiovascular. Objetivo: Determinar las variaciones en la dinámica no lineal de la regulación autonómica cardiovascular durante la prueba del peso sostenido en pacientes con diabetes mellitus tipo 2. Método: Estudio cuasiexperimental, antes-después, con grupo control, realizado en junio-agosto de 2018 en la Facultad No. 1 de Medicina de Santiago de Cuba. Se trabajó con 15 pacientes que padecían diabetes mellitus tipo 2 sin otra enfermedad asociada y 15 sujetos sanos, a quienes se les aplicó la prueba del peso sostenido. Resultados: En los pacientes con diabetes mellitus, al realizar la prueba del peso sostenido se produjo un aumento significativo en la presión arterial sistólica, diastólica y media, y en la frecuencia cardiaca. En la entropía muestral, parámetro que evalúa la adaptabilidad de los sistemas, se produjo una disminución significativa (2.28 ± 0.33 vs. 1.83 ± 0.47 ms; p = 0.003143). El valor del estadístico C de la entropía muestral en estado basal quedó establecido en 0.973, siendo la variable con mayor capacidad predictiva. Conclusiones: Durante la prueba del peso sostenido en los pacientes con diabetes mellitus tipo 2 se produjo una disminución de la complejidad de la regulación autonómica cardiovascular; la entropía muestral basal constituyó el indicador de mayor eficacia en la identificación de alteraciones autonómicas cardiovasculares.

Abstract Introduction: The analysis of non-linear dynamics of cardiovascular autonomic regulation based on heart rate variability has not been previously studied in patients with type 2 diabetes mellitus using the sustained weight test as an inducer of cardiovascular hyperreactivity. Objective: To determine the variations in the non-linear dynamics of cardiovascular autonomic regulation during the sustained weight test in patients with type 2 diabetes mellitus. Method: A quasi-experimental, before-after study with a control group, from June-August 2018, at the No. 1 School of Medicine in Santiago de Cuba. We worked with 15 patients suffering from type 2 diabetes mellitus without other associated disease and 15 healthy subjects, to whom the sustained weight test was applied. Results: In patients with diabetes mellitus, when performing the sustained weight test, there was a significant increase in the hemodynamic parameters TAS, TAD, TAM and FC. In the sample entropy, a parameter that evaluates the adaptability of the systems, there is a significant decrease (2.28 ± 0.33 vs. 1.83 ± 0.47 ms; p = 0.003143). The value of the C statistic of the sample entropy at baseline was established at 0.973, being the variable with the highest predictive capacity. Conclusions: In patients with type 2 diabetes mellitus during the sustained weight test, there was a decrease in the complexity of cardiovascular autonomic regulation, the basal sample entropy was the indicator of greater efficacy in the identification of cardiovascular autonomic alterations.

Linear and Nonlinear Heart Rate Variability Analysis in Gonadal Dysgenesis (Swyer Syndrome): A Case Report

Abstract Swyer syndrome is one of the disorders of sexual differentiation. Previous studies have demonstrated increased sympathetic activity with heart rate variability (HRV) analysis with decreasing estradiol levels. One patient presented a pure 46, XY gonadal dysgenesis with female phenotype. Cardiac autonomic modulation was assessed through HRV analysis while at rest. This research analyzed linear and nonlinear indexes. HRV analysis showed reduced parasympathetic and global modulation with an apparent increase in sympathetic tone and a loss of HR fractal dynamics toward correlated behavior, characterized by low entropy and high determinism of time series.

Confirmación diagnóstica de la metodología diseñada para evaluar los registros Holter durante 18 horas mediante la entropía proporcional / Diagnostic confirmation of the methodology designed to evaluate the Holter registers for 18 hours through proportional entropy

Resumen Introducción: Los sistemas dinámicos, la entropía y la probabilidad han contribuido de forma significativa al desarrollo de nuevas metodologías que caracterizan al grado de complejidad de la dinámica cardíaca. Objetivo: Confirmar la aplicabilidad clínica de la metodología fundamentada en la teoría de los sistemas dinámicos, la probabilidad y la entropía para evaluar la dinámica cardíaca durante 18 horas. Material y métodos: Se tomaron 570 registros Holter normales en diferentes enfermedades. Para cada uno se construyó un atractor en un mapa de retardo y se evaluó la probabilidad de ocupación de pares ordenados de frecuencias cardíacas durante 18 horas, así como la entropía y sus proporciones. Se compararon las medidas obtenidas con los valores de normalidad y enfermedad establecidos previamente para obtener el diagnóstico matemático de cada Holter. Las conclusiones del Holter se revelaron luego de aplicar la metodología fisicomatemática para calcular sensibilidad, especificidad y coeficiente kappa respecto de la norma de referencia clínica. Resultados: Con las proporciones de la entropía de los atractores se diferenciaron dinámicas cardíacas agudas, crónicas, normales y la evolución entre estos estados con resultados de sensibilidad y especificidad del 100% con una concordancia entre la norma de referencia y el diagnóstico fisicomatemático evaluado con el coeficiente kappa de 1. Conclusiones: Este estudio confirma que la metodología aplicada logra diagnosticar objetivamente la dinámica cardíaca, ya que establece predicciones de estados de normalidad o del nivel de agravamiento de la dinámica, y evidencia la aplicabilidad de esta metodología, lo cual sugiere su potencial uso en el contexto clínico.

Abstract Introduction: Dynamic systems, entropy and probability have contributed significantly in the development of new methodologies that characterize the degree of complexity of cardiac dynamics. Objective: To confirm the clinical applicability of the methodology based on the theory of dynamic systems, probability and entropy to evaluate cardiac dynamics during 18 hours. Material and methods: 570 normal Holter records with different pathologies were taken. For each one an attractor was built on the delay map and the probability of occupation of ordered pairs of heart rates during 18 hours was evaluated, as well as the entropy and its proportions. The measurements obtained were compared with the values of normality and illness established previously to obtain the mathematical diagnosis of each Holter. The conclusions of the Holter were unblinded after having applied the physical-mathematical methodology to calculate sensitivity, specificity and Kappa coefficient with respect to the Gold-Standard. Results: With the proportions of the entropy of the attractors, acute, chronic, normal, and evolution cardiac dynamics were differentiated between these states. the application of the methodology showed a sensitivity and specificity of 100 %. The agreement between the Gold-Standard and the physical-mathematical diagnosis evaluated with the kappa coefficient was 1. Conclusions: This study confirms that the applied methodology manages to objectively diagnose cardiac dynamics, establishing predictions of normality states or the level of aggravation of the dynamics, evidencing the applicability of this methodology, suggesting its potential use in the clinical context.

The role of absolute humidity in respiratory mortality in Guangzhou, a hot and wet city of South China

BACKGROUND@#For the reason that many studies have been inconclusive on the effect of humidity on respiratory disease, we examined the association between absolute humidity and respiratory disease mortality and quantified the mortality burden due to non-optimal absolute humidity in Guangzhou, China.@*METHODS@#Daily respiratory disease mortality including total 42,440 deaths from 1 February 2013 to 31 December 2018 and meteorological data of the same period in Guangzhou City were collected. The distributed lag non-linear model was used to determine the optimal absolute humidity of death and discuss their non-linear lagged effects. Attributable fraction and population attributable mortality were calculated based on the optimal absolute humidity, defined as the minimum mortality absolute humidity.@*RESULTS@#The association between absolute humidity and total respiratory disease mortality showed an M-shaped non-linear curve. In total, 21.57% (95% CI 14.20 ~ 27.75%) of respiratory disease mortality (9154 deaths) was attributable to non-optimum absolute humidity. The attributable fractions due to high absolute humidity were 13.49% (95% CI 9.56 ~ 16.98%), while mortality burden of low absolute humidity were 8.08% (95% CI 0.89 ~ 13.93%), respectively. Extreme dry and moist absolute humidity accounted for total respiratory disease mortality fraction of 0.87% (95% CI - 0.09 ~ 1.58%) and 0.91% (95% CI 0.25 ~ 1.39%), respectively. There was no significant gender and age difference in the burden of attributable risk due to absolute humidity.@*CONCLUSIONS@#Our study showed that both high and low absolute humidity are responsible for considerable respiratory disease mortality burden, the component attributed to the high absolute humidity effect is greater. Our results may have important implications for the development of public health measures to reduce respiratory disease mortality.

Effects of Temperature on Outpatient Visits for Urticaria among Lanzhou Residents Based on Distributed Lag Non-linear Model / 中国医学科学院学报

Objective To evaluate the influence of temperature on the outpatient visits for urticaria in Lanzhou City and its hysteresis and to find out the sensitive populations by sex and age stratification.Methods We collected the urticaria outpatient data in three grade A class three hospitals as well as the meteorological data and air pollutant data in Lanzhou from January 2011 to December 2017.The distributed lag non-linear model(DLNM)was employed to analyze the influence of daily mean temperature on the outpatient visits for urticaria.Stratification analysis was performed for different age groups(0-14,15-59,≥60 years)and different sex populations.Results Temperature had a non-linear relationship with the outpatient visits for urticaria,and there existed hysteresis.During the research period,the average daily outpatient visits for urticaria at the three hospitals in Lanzhou was 25,ranging from 1 to 76.With the rise in the daily mean temperature within 0-10 ℃,the risk of outpatient visits for urticaria first increased and then decreased.When the daily mean temperature was 2 ℃,hysteresis occurred on the 18th day,and the relative risk(

Realization of non-invasive blood glucose detector based on nonlinear auto regressive model and dual-wavelength / 生物医学工程学杂志

The use of non-invasive blood glucose detection techniques can help diabetic patients to alleviate the pain of intrusive detection, reduce the cost of detection, and achieve real-time monitoring and effective control of blood glucose. Given the existing limitations of the minimally invasive or invasive blood glucose detection methods, such as low detection accuracy, high cost and complex operation, and the laser source's wavelength and cost, this paper, based on the non-invasive blood glucose detector developed by the research group, designs a non-invasive blood glucose detection method. It is founded on dual-wavelength near-infrared light diffuse reflection by using the 1 550 nm near-infrared light as measuring light to collect blood glucose information and the 1 310 nm near-infrared light as reference light to remove the effects of water molecules in the blood. Fourteen volunteers were recruited for

Impact of chronic obstructive pulmonary disease on linear and nonlinear dynamics of heart rate variability in patients with heart failure

The objective of this study was to investigate the impact of chronic obstructive pulmonary disease (COPD)-heart failure (HF) coexistence on linear and nonlinear dynamics of heart rate variability (HRV). Forty-one patients (14 with COPD-HF and 27 HF) were enrolled and underwent pulmonary function and echocardiography evaluation to confirm the clinical diagnosis. Heart rate (HR) and R-R intervals (iRR) were collected during active postural maneuver (APM) [supine (10 min) to orthostasis (10 min)], respiratory sinus arrhythmia maneuver (RSA-M) (4 min), and analysis of frequency domain, time domain, and nonlinear HRV. We found expected autonomic response during orthostatic changes with reduction of mean iRR, root mean square of successive differences between heart beats (RMSSD), RR tri index, and high-frequency [HF (nu)] and an increased mean HR, low-frequency [LF (nu)], and LF/HF (nu) compared with supine only in HF patients (P<0.05). Patients with COPD-HF coexistence did not respond to postural change. In addition, in the orthostatic position, higher HF nu and lower LF nu and LF/HF (nu) were observed in COPD-HF compared with HF patients. HF patients showed an opposite response during RSA-M, with increased sympathetic modulation (LF nu) and reduced parasympathetic modulation (HF nu) (P<0.05) compared with COPD-HF patients. COPD-HF directly influenced cardiac autonomic modulation during active postural change and controlled breathing, demonstrating an autonomic imbalance during sympathetic and parasympathetic maneuvers compared with isolated HF.

Nursing Now and Nursing in the future: the experience of the unexpected irruptions / Nursing Now and Nursing in the future: a experiência das irrupções do inesperado / Nursing Now and Nursing in the future: experiencia de las irrupciones de lo inesperado

Objective: to carry out a theoretical reflection on the Nursing Now Campaign and the experience of the unexpected irruptions facing the pandemic period. Method: a theoretical-reflective study, supported by the theoretical framework of complexity thinking. It aims at understanding the dialogic between the notions of order, disorder and organization, which translate the transition from simplification to complexity of the pandemic phenomenon and its relation to the theme of Nursing Now and Nursing in the future. Results: the universe of phenomena is simultaneously composed of order, disorder and organization. Reasserting the central role of Nursing in the health team, facing the irruptions and uncertainties caused by the current pandemic, implies the ability to dialog with disorder and raise a new and more complex global (re)organization of the being and doing Nursing. Conclusion: in addition to answers, theoretical reflection raises new questions and irruptions. The inseparability between the notions of order and disorder in the evolutionary dynamics of the Nursing system is conceived and the promotion of even more complex levels of organization, management and Nursing assistance to achieve universal access to health is advocated.

Objetivo: realizar reflexão teórica acerca da Campanha Nursing Now e a experiência das irrupções do inesperado face ao período pandêmico. Método: estudo teórico-reflexivo, apoiado no referencial teórico do pensamento da complexidade. Visa-se à compreensão da dialógica entre as noções de ordem, de desordem e de organização, as quais traduzem a passagem da simplificação à complexidade do fenômeno da pandemia e sua relação com a temática Nursing Now and Nursing in the future. Resultados: o universo dos fenômenos é tecido, simultaneamente, de ordem, de desordem e de organização. Reafirmar o papel central da Enfermagem na equipe de saúde, face às irrupções e incertezas provocadas pela pandemia em curso, implica capacidade de dialogar com a desordem e suscitar uma nova e mais complexa (re)organização global do ser e do fazer Enfermagem. Conclusão: a reflexão teórica suscita, além de respostas, novos questionamentos e novas irrupções. Concebe-se a inseparabilidade entre as noções de ordem e de desordem na dinâmica evolutiva do sistema de Enfermagem e defende-se a promoção de níveis de organização, gestão e assistência de Enfermagem ainda mais complexos para o alcance do acesso universal à saúde.

Objetivo: realizar una reflexión teórica sobre la Campaña Nursing Now y la experiencia de las irrupciones de lo inesperado ante el período pandémico. Método: estudio teórico-reflexivo, basado en el marco teórico del pensamiento complejo. Tiene como objetivo comprender la dialógica entre las nociones de orden, desorden y organización, que traducen la transición de la simplificación a la complejidad del fenómeno pandémico y su relación con el tema Nursing Now and Nursing in the future. Resultados: el universo de los fenómenos se entreteje, simultáneamente, de orden, desorden y organización. Reafirmar el papel central de la Enfermería en el equipo de salud, ante las irrupciones e incertidumbres provocadas por la pandemia actual, implica la capacidad de dialogar con el desorden y propiciar una nueva y más compleja (re)organización global del ser y hacer Enfermería. Conclusión: la reflexión teórica plantea, además de respuestas, nuevas interrogantes y nuevas irrupciones. Se concibe la inseparabilidad entre las nociones de orden y desorden en la dinámica evolutiva del sistema de Enfermería y se aboga por la promoción de niveles aún más complejos de organización, gestión y asistencia de Enfermería para lograr el acceso universal a la salud.

Diferencias inter e intra-hemisféricas de dinámicas no lineales en las señales de electroencefalograma durante la resolución de una prueba de atención / Inter- and intra-hemispheric differences of non-linear dynamics in electroencephalogram signals during the execution of an attention test

Resumen Introducción. La actividad cerebral, teniendo en cuenta su dinámica aperiódica, puede ser estudiada mediante funciones no lineales o sistemas caóticos. Objetivo. Estudiar las diferencias inter e intra-hemisféricas de la relación orden/caos en la actividad cerebral de la onda beta en estudiantes universitarios durante la resolución de un test de atención. Materiales y métodos. La muestra estuvo compuesta por 10 estudiantes universitarios de educación física, todos hombres, a quienes se les aplicó la prueba de atención de Toulouse-Piéron para registrar, mediante electroencefalograma, su actividad cerebral por 8 minutos durante la ejecución de la prueba. Para el registro de la actividad cerebral se usó el dispositivo Emotiv Epoc®. Resultados. Se observaron diferencias intra e inter-hemisfericas en la relación orden/caos entre los participantes en las regiones prefrontales, temporales y occipitales (p<0.05), así como diversas correlaciones entre estas regiones (r>0.600), las cuales variaron tanto entre los sujetos, como a nivel individual a medida que avanzaba la ejecución de la prueba. Conclusión. A medida que la ejecución de la prueba avanzaba, las asimetrías hemisféricas aumentaban, por lo que es posible concluir que la participación en procesos cognitivos continuos produce diferencias en la actividad cerebral; sin embargo, es necesario realizar estudios similares en muestras con diferentes características (diversos grupos etarios, mujeres, etc.) y donde se apliquen otras pruebas de atención para poder confirmar o contrastar los resultados aquí reportados.

Abstract Introduction: Considering its aperiodic dynamics, brain activity can be studied by means of non-linear functions or chaotic systems. Objective: To analyze the inter- and intra-hemispheric differences of the order/chaos relationship observed in the beta waves of university students during their participation in an attention test. Materials and methods: The sample was composed of 10 university physical education students, all males, who were administered the Toulouse-Piéron Concentrated Attention Test to record, by means of electroencephalogram, their brain activity for 8 minutes during the execution of the test. The Emotiv Epoc® device was used to record brain activity. Results: Intra- and inter-hemispheric differences were observed in the order/chaos relationship among the participants in the prefrontal, temporal and occipital regions (p<0.05), as well as various correlations between these regions (r>0.600), which varied both between participants and individually as the execution of the test progressed. Conclusion: As the test progressed, hemispheric asymmetries increased, which allows concluding that engaging in continuous cognitive processes causes brain activity differences. However, it is necessary to carry out similar studies in samples with different characteristics (different age groups, women, etc.) in which other attention tests are used to confirm or contrast the results reported here.

Estabilidad de la actividad eléctrica no lineal durante condiciones basales con los ojos cerrados / Nonlinear electrical activity stability in basal, eyes closed conditions

Introducción: El electroencefalograma permite registrar la actividad eléctrica cerebral en estado de reposo y durante la ejecución de tareas cognitivas. Objetivo: Evaluar si la actividad cerebral, analizada como dinámica no lineal, se mantiene estable durante diferentes ventanas temporales en una condición basal con ojos cerrados. Métodos: Se realizaron registros con electroencefalograma durante dos minutos a 14 estudiantes universitarios varones. Posteriormente, se compararon las medias de índices de Hurst (H) en ventanas temporales de 60, 30 y 10 segundos. Resultados: Las medias de los índices H son estables a través de diferentes ventanas temporales en las regiones prefrontales, temporales y occipitales. Conclusiones: Los registros de electroencefalograma en condiciones basales con los ojos cerrados son válidos para comparar protocolos experimentales de resolución de problemas cognitivos utilizando el exponente de Hurst en los sujetos de la muestra y en otros con características similares(AU)

Introduction: Electroencephalography makes it possible to record brain electrical activity at rest and during the performance of cognitive tasks. Objective: Determine whether brain activity analyzed as nonlinear dynamics remains stable during various time windows in basal, eyes closed conditions. Methods: Electroencephalographic records of 14 male university students were taken during two minutes. Hurst's index means (H) were then compared in time windows of 60, 30 and 10 seconds. Results: H index means are stable throughout the various time windows in the prefrontal, temporal and occipital regions. Conclusions: Electroencephalographic records in basal, eyes closed conditions are valid to compare experimental protocols for cognitive problem solving using the Hurst exponent in subjects from the sample as well as others of similar characteristics(AU)

Nonlinear regression analysis of length growth in cultured rainbow trout / [Análise não linear do crescimento em comprimento de truta-arco-íris de aquicultura ]

Length growth as a function of time has a non-linear relationship, so nonlinear equations are recommended to represent this kind of curve. We used six nonlinear models to calculate the length gain of rainbow trout (Oncorhynchus mykiss) during the final grow-out phase of 98 days under three different feed types in triplicate groups. We fitted the von Bertalanffy, Gompertz, Logistic, Brody, Power Function, and Exponential equations to individual length-at-age data of 900 fish. Equations were fitted to the data based on the least square method using the Marquardt iterative algorithm. Accuracy of the fitted models was evaluated using a model performance metrics combining mean squared residuals (MSR), mean absolute error (MAE) and Akaike's Information Criterion corrected for small sample sizes (AICc). All models converged in all cases tested. Evaluation criteria for the Logistic model indicated the best overall fit (0.67 of combined metric MSR, MAE and AICc) under all different feeding types, followed by the Exponential model (0.185), and the von Bertalanffy and Brody model (0.074, respectively). Additionally, ∆AICc results identify the Logistic and Gompertz models as being substantially supported by the data in 100% of cases. The logistic model can be suggested for length growth prediction in aquaculture of rainbow trout.(AU)

O crescimento em comprimento em função do tempo tem uma relação não linear; por isso, funções não lineares são recomendáveis para descrever essa relação. Seis modelos não lineares foram usados para calcular o ganho em comprimento de truta-arco-íris (Oncorhynchus mykiss) durante 98 dias, na fase final da engorda, submetidas a três dietas diferentes em grupos triplicados. Foram ajustadas as equações de von Bertalanffy, Gompertz, logístico, Brody, função potencial e exponencial a dados individuais de comprimento-idade de 900 peixes. O ajuste foi feito pelo método dos mínimos quadrados, usando-se o algoritmo iterativo de Marquardt. A precisão do ajuste foi avaliada pelo uso de critérios combinados de ajuste: quadrado médio do resíduo (QMR), erro médio absoluto (EMA) e o critério de informação de Akaike corrigido para tamanhos amostrais pequenos (AICc). Todos os modelos atingiram a convergência para cada caso avaliado. Os critérios de avaliação do modelo logístico indicaram o melhor ajuste geral (0,67 vez dos critérios combinados MSR, MAE e AICc) para cada grupo de peixe avaliado, seguido pelo modelo exponencial (0,185) e os modelos von Bertalanffy e Brody, com 0,074, respectivamente. Similarmente, os resultados de ΔAICc identificaram-se ao modelo logístico e ao de Gompertz, com grande suporte das informações em 100% dos casos. Por fim, o modelo logístico pode ser sugerido na predição do crescimento em comprimento de truta-arco-íris cultivada.(AU)

Von Mises stresses on Mushroom-loop archwires for incisor retraction: a numerical study

ABSTRACT Objective: To perform a numerical simulation using FEM to study the von Mises stresses on Mushroom archwires. Methods: Mushroom archwires made of titanium-molybdenum alloy with 0.017 x 0.025-in cross-section were used in this study. A YS of 1240 MPa and a Young's modulus of 69 GPa were adopted. The archwire was modeled in Autodesk Inventor software and its behavior was simulated using the finite element code Ansys Workbench (Swanson Analysis Systems, Houston, Pennsylvania, USA). A large displacement simulation was used for non-linear analysis. The archwires were deformed in their extremities with 0° and 45°, and activated by their vertical extremities separated at 4.0 or 5.0 mm. Results: Tensions revealed a maximum of 1158 MPa at the whole part of the loop at 5.0mm of activation, except in a very small area situated at the top of the loop, in which a maximum of 1324 Mpa was found. Conclusions: Mushroom loops are capable to produce tension levels in an elastic range and could be safely activated up to 5.0mm.

RESUMO Objetivo: Realizar uma simulação numérica, por meio do Método dos Elementos Finitos (MEF), para obter as tensões de von Mises em arcos Mushroom. Métodos: Foram usados arcos com geometria Mushroom de titânio-molibdênio, com secção transversal 0,017" x 0,025". Adotou-se valores de tensão de escoamento (σesc) de 1.240 MPa e módulo de elasticidade (E) de 69 GPa. O arco foi modelado por meio do software Autodesk Inventor, e seu desempenho foi simulado utilizando-se o software de elementos finitos Ansys Workbench (Swanson Analysis System, Houston, Pennsylvania, EUA). Para a simulação, foi considerada a análise para grandes deslocamentos. O arco foi conformado em suas extremidades considerando-se planos de 0° e 45°, pré-ativado em 2,5mm e ativado por meio de suas extremidades verticais, separadas 4,0 mm ou 5,0 mm. Resultados: As tensões revelaram um valor máximo de 1.158 MPa na maior parte da alça, aos 5,0 mm de ativação, com exceção de uma área muito pequena, com valor de 1.324 MPa, situada no topo da alça. Conclusões: Os arcos Mushroom são capazes de produzir níveis de tensão situados dentro da região elástica e poderiam ser ativados com segurança até os 5,0 mm de ativação.

Pandemia de la coviD-19 y las Políticas de Salud Pública en el Perú: marzo-mayo 2020 / COVID-19 pandemic and Public Health Policies in Peru: March-May 2020

RESUMEN Objetivo El trabajo tiene como objetivo analizar la dinámica del comportamiento de la COVID-19 en el Perú, estimar y evaluar el impacto de la política pública de supresión (cuarentena). Métodos El modelo epidemiológico SIR y la estimación con el método de Mínimos Cuadrados Ordinarios (MCO). Resultados Se encontró que el número básico de propagación (Ro) cayó de 6,0 a 3,2 habiéndose reducido en 54% por efecto de la estrategia de supresión, y dos meses después cayó a 1,7. Sin embargo, sigue siendo alto y evidencia que aún continúa en expansión el nivel de infectados, con los efectos sociales y económicos adversos que esta medida implica. Conclusión La COVID-19 es una enfermedad que crece exponencialmente, por lo cual, la política de salud basada en la estrategia de supresión ha permitido aplanar la curva de contagio, evitando el colapso del Sistema de Salud.(AU)

ABSTRACT Objective The objective of the study is to analyze the behavior dynamics of COVID-19 in Peru, estimate and evaluate the impact of the suppression public policy (quarantine). Methods The SIR epidemiological model and the estimation with the ordinary Least Squares (OLS) method. Results It was found that the basic number of propagation (Ro) fell from 6,0 to 3,2 having been reduced by 54% due to the suppression strategy; and two months later it falls to 1,7. However, it remains high and evidence that the level of those infected continues to expand with its adverse social and economic effects. Conclusion: COVID-19 is a disease that grows exponentially, and that the health policy based on the suppression strategy has allowed to flatten the contagion curve, thus avoiding the collapse of the Health System.(AU)

La relación de la edad con los componentes espectrales de las realizaciones sin ruido de señales fotopletismográficas: resultados de un enfoque de identificación no lineal / Relationship of Age with Spectral Components of Noise-Free Realizations of Photoplethysmographic Signals: Outcomes of a Nonlinear Identification Approach

Background: Age-related changes in the vascular network have been widely documented, however, nonlinear identification has been poorly applied to the analysis of cardiovascular signals. Objective: To determine the impact of age on spectral components of Noise-free realizations (NFR) obtained from photoplethysmographic signals, summarized in the Kernel Complexity Regressive Index (KCRIndex). Methods: With 190 apparently healthy participants (9 to 89 years) from Orense, Spain, Photoplethysmographic signals were recorded during 5 minutes in supine position using Nellcor-395 pulse oximeter; signals were digitized at 1000 Hz, and furtherly submitted to nonlinear identification via a kernel nonlinear autoregressive estimator. KCRIndex is defined as the average of at least three negative slope values at the NFR log-log spectrum in the 9 to 25 Hz frequency region. Results: KCRIndex decreased with age in a linear fashion and did not differ between genders. The regression line obtained was KCRIndex=-0.025*age+6.868 (r=-0.751). Conclusions: KCRIndex, is strongly correlated with age, thus opening up new possibilities for cardiovascular exploration at primary health care settings and even on open field conditions(AU)

Antecedentes: los cambios relacionados con la edad en la red vascular se han documentado ampliamente, sin embargo, la identificación no lineal solo se ha aplicado de manera esporádica al análisis de las señales cardiovasculares. Objetivo: determinar los cambios con la edad en los componentes espectrales de las realizaciones sin ruido (NFR) obtenidas a partir de señales fotopletismográficas, resumidas en el índice regresivo de la complejidad por núcleos (KCRIndex). Métodos: Con 190 participantes aparentemente sanos (de 9 a 89 años) residentes en Orense, España, se registraron señales fotopletismográficas durante 5 minutos en posición supina usando un oxímetro de pulso Nellcor-395; las señales se digitalizaron a 1000 Hz, y se sometieron a identificación no lineal a través de un estimador autorregresivo no lineal por núcleos. El KCRIndex se define como el promedio de al menos tres valores de pendiente negativos en el espectro log-log de NFR en la región de frecuencia de 9 a 25 Hz. Resultados: KCRIndex disminuyó con la edad de forma lineal y no difirió entre géneros. La línea de regresión obtenida fue KCRIndex = -0.025 * edad + 6.868 (r = -0.751). Conclusiones: Este índice propuesto está fuertemente correlacionado con la edad, lo que abre nuevas posibilidades para la exploración cardiovascular en entornos de atención primaria de salud e incluso en condiciones de campo(AU)