Smooth transitions, asymmetric adjustment and unit roots

The aim of this paper is to develop a unit root test that takes into account two sources of nonlinearites in data, i.e. asymmetric speed of mean reversion and structural changes. The asymmetric speed of mean reversion is modeled by means of a exponential smooth transition autoregression (ESTAR) function for the autoregressive parameter, whereas structural changes are approximated by a smooth transition in the deterministic components. We find that the proposed test performs well in terms of size and power, in particular when the autoregressive parameter is close to one

Nonlinear trend stationarity of real exchange rates: the case of the Mediterranean countries

The aim of this article is to provide additional evidence on the fulfilment of the Purchasing Power Parity hypothesis in the so-called Mediterranean countries. In order to test for the empirical validity of such hypothesis, we have applied two types of unit root tests. The first group is due to Bierens (1997) who generalizes the alternative hypothesis to nonlinear trend stationariry and, the second is the Leybourne, Newbold and Vougas (1998) approach that uses a nonlinear specification for the intercept and slope in order to detrend the series. The results suggest that the evidence in favour of the Purchasing Power Parity hypothesis increases when we allow for nonlinear alternatives

Real convergence in Europe: a cluster analysis

In this paper we analyse real convergence in GDP per worker in the EU member states. The aim is to test whether there is evidence of club convergence in the EU, i.e. divergence in GDP per worker. Evidence in favour of cluster or club convergence may be an indication of significant productivity divergences between countries, which may also explain the current turmoil in the euro zone. The results show evidence of different economic growth rates within Europe, which also converge to different steady states, implying divergence in the EU-14. Within the EU-14 member states we observe two convergence clubs, which are not related to the fact that some countries belong to the euro area. Furthermore, Eastern European countries are also divided in two clubs, with a more direct effect of belonging to the euro zone in the composition of the clubs

Energy Prediction in Urban Photovoltaic Systems

Este artículo propone un nuevo método para estimar la potencia y energía producida por sistemas fotovoltaicos urbanos, los cuales son comúnmente cubiertos por sombras que afectan su desempeño. La solución se basa en un algoritmo para procesar, rápidamente, un modelo preciso que considera el efecto de las sombras. Esta solución provee un mejor desempeño en comparación con aproximaciones clásicas, ya que reduce significativamente el tiempo de cálculo sin introducir errores sensibles, permitiendo la simulación de largos periodos de operación, e.g. meses y años. Por lo tanto, esta solución es apropiada para realizar estimaciones de energía orientadas a análisis económicos, e.g. cálculo del tiempo de retorno de la inversión, así como para soportar el diseño de instalaciones fotovoltaicas, permitiendo el cálculo preciso del número de módulos requeridos para suplir el perfil de carga.This paper proposes a new method to accurately estimate the power and energy production in urban photovoltaic (PV) systems, which are commonly covered by shades affecting its performance. The solution is based on an efficient algorithm designed to compute, in short time, an accurate model accounting for the shades impact. In such a way, the proposed approach improves classical solutions by significantly reducing the processing time to simulate long periods, e.g. months and years, but without introducing sensible errors. Therefore, this approach is suitable to estimate the production of PV systems for economical analyses such as the return-of-invested time calculation, but also to accurately design PV installations by selecting the right number of photovoltaic modules to supply the required load power.  

Modeling of PV Systems Based on Inflection Points Technique Considering Reverse Mode

Este artículo propone una metodología para el modelado de sistemas fotovoltaicos, considerando su comportamiento tanto en el modo de operación directo como en modo inverso bajo condiciones no uniformes de irradiación. La metodología propuesta se basa en la técnica de puntos de inflexión con una aproximación lineal del modelo del diodo de bypass y un modelo simplificado del módulo fotovoltaico. El modelo matemático planteado permite evaluar el rendimiento energético de un sistema fotovoltaico, con tiempos cortos de simulación para arreglos de gran tamaño. Adicionalmente, esta metodología permite estimar el estado de los módulos afectados por el sombreo parcial ya que es posible conocer la potencia disipada debido a la operación en el segundo cuadrante.This paper proposes a methodology for photovoltaic (PV) systems modeling, considering their behavior in both direct and reverse operating mode and considering mismatching conditions. The proposed methodology is based on the inflection points technique with a linear approximation to model the bypass diode and a simplified PV model. The proposed mathematical model allows to evaluate the energetic performance of a PV system, exhibiting short simulation times in large PV systems. In addition, this methodology allows to estimate the condition of the modules affected by the partial shading since it is possible to know the power dissipated due to its operation at the second quadrant

Agresión hacia personal de salud : ¿una epidemia global?

Las agresiones contra el personal de salud vienen aumentando en el mundo entero. Esa impresión, por lo menos, es la que queda al dar una mirada a la literatura internacional. Cuando se hace una búsqueda en el portal PubMed, empleando las palabras clave 'agresión' y 'personal de salud '("Aggression" [Mesh] AND "Health Personnel" [Mesh]), se observa que de cerca de una docena de publicaciones anuales hace 25 años, hemos pasado a más de un centenar en años recientes.22-2

Benefits of Adding an Aquatic Resistance Interval Training to a Nutritional Education on Body Composition, Body Image Perception and Adherence to the Mediterranean Diet in Older Women

The human population is increasing due to lengthening life expectancy, but the quality of life and health of people is moving in the opposite direction. The purpose of this study is to evaluate how aquatic resistance interval training can influence body composition, body image perception and adherence to the Mediterranean diet (MD) in older women participants in a nutrition education program and to study the relation between these variables. Thirty-four participants aged 69 ± 4 years were randomly assigned into two groups: experimental (aquatic resistance interval training plus nutritional intervention) and control (nutritional intervention). The intervention consisted of resistance training in an aquatic environment carried out for 14 weeks (three sessions per week; 60 min each). Body composition, body image perception and adherence to MD diet were evaluated at baseline and 14 weeks. No significant differences were found between groups regarding body image perception and adherence to the MD. There was a significant increase in muscle mass (kg) (p < 0.001) and a significant decrease in fat mass (kg) (p < 0.001) in the intervention group when compared to the control group. The addition of aquatic resistance interval training to a nutritional intervention was not sufficient to change body image perception and adherence to MD but produced improvement in body composition (through an increase in muscle mass and decrease on fat mass) in older women

Analysis of the flow-volume curve in children and adolescents with allergic rhinitis without asthma

Introducción. Existen evidencias epidemiológicas, funcionales y patológicas que vinculan las vías aéreas superior e inferior, reconocidas clínicamente como una vía aérea única. Los pacientes con rinitis alérgica sin asma podrían presentar anormalidades espirométricas subclínicas. Objetivos. Describir los resultados de las curvas fujo-volumen en un grupo de pacientes con rinitis alérgica sin asma y analizar las posibles asociaciones entre las variables antropométricas, clínicas y bioquímicas con los resultados anormales de las pruebas espirométricas. Población y métodos. Estudio observacional descriptivo, en el que se incluyeron niños y adolescentes de entre 6 y 18 años con síntomas de rinitis alérgica sin asma. Se estableció la edad, el sexo, el índice de masa corporal y la duración de la rinitis por la historia clínica. Se realizaron pruebas cutáneas con alérgenos, espirometría por curva fujo-volumen, determinación de eosinóflos en la sangre y la secreción nasal, e IgE sérica total. Resultados. Se estudiaron 84 pacientes; 21 (25%; IC 95% 15,1 a 34,8) presentaron alguna variable espirométrica alterada. El índice FEV1/FVC fue el más afectado (10/84; 12% IC 95% 4,3 a 19,4). El análisis de regresión logística múltiple determinó que la alteración espirométrica se asoció con el número de eosinóflos en la sangre (OR 1,00229; IC 95% 1,00022 a 1,00436; p= 0,03) y el índice de masa corporal (OR 1,31282; IC 95% 1,08611 a 1,58685; p= 0,0049). Conclusiones. Los resultados muestran la presencia de alteraciones espirométricas en un importante porcentaje de niños y adolescentes con rinitis alérgica sin asma. El recuento absoluto de eosinóflos en la sangre y el índice de masa corporal estarían asociados a la alteración subclínica de la función pulmonar.Fil: Ianero, Luciano. Universidad Catolica de Cordoba. Facultad de Medicina. Clinica Universitaria Reina Fabiola; ArgentinaFil: Saranz, Ricardo J.. Universidad Catolica de Cordoba. Facultad de Medicina. Clinica Universitaria Reina Fabiola; ArgentinaFil: Lozano, Natalia I.. Universidad Catolica de Cordoba. Facultad de Medicina. Clinica Universitaria Reina Fabiola; ArgentinaFil: Lozano, Alejandro. Universidad Catolica de Cordoba. Facultad de Medicina. Clinica Universitaria Reina Fabiola; ArgentinaFil: Sasia, Laura. Universidad Catolica de Cordoba. Facultad de Medicina. Clinica Universitaria Reina Fabiola; ArgentinaFil: Ramirez, Maximiliano. Universidad Nacional de Cordoba. Facultad de Medicina; ArgentinaFil: Cuestas, Eduardo. Universidad Catolica de Cordoba. Facultad de Medicina; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Plyometric Training in Female Volleyball Players. Systematic Review

El voleibol femenino se práctica en todo el mundo a nivel profesional y amateur. Los saltos verticales son una parte fundamental para el desarrollo de este deporte, por lo que el entrenamiento pliométrico puede ser eficaz para un aumento del rendimiento. El propósito de estudio fue describir cuáles han sido los métodos y programas de entrenamiento pliométrico en mujeres que practican voleibol, así como el resultado obtenido en función de estos. El proceso de búsqueda en las bases de datos se llevó a cabo desde Marzo hasta Junio de 2016. Las bases de datos consultadas fueron Pubmed, Web of Science, Cochrane y SPORTDiscus. La revisión sistemática fue realizada bajo las recomendaciones de la declaración PRISMA. La calidad metodológica de los estudios fue evaluada mediante la Escala PEDro. Como resultado, se obtuvieron un total de 205 artículos tras eliminar aquellos que estaban por duplicado. Finalmente 7 artículos fueron seleccionados. Los resultados principales fueron que aquellos estudios que utilizan deportistas amateurs obtienen mejores resultados que los realizados con deportistas profesionales cuando se realizan programas de entrenamiento pliométrico. También se indica que un período de entrenamiento pliométrico de baja intensidad puede prevenir una disminución en la altura del salto vertical; así como es necesario programar la pretemporada para evitar pérdida en la capacidad de salto. Todo ello parece indicar, como conclusión, que es necesario una disminución del volumen y un aumento de la intensidad en el entrenamiento pliométrico.Female volleyball is practiced all over the world at a professional and amateur level. Vertical jumps are a fundamental part of the development of this sport. In this sense, plyometric training can be effective for increased performance. The purpose of the study was to describe the methods and programs of plyometric training in women volleyball players, as well as the results obtained from them. The following electronic databases were searched March to June 2016. Electronic databases consulted were Pubmed, Web of Science, Cochrane and SPORTDiscus. This systematic review was performed following PRISMA statement. PEDro scale was used to evaluated the methodological quality of the included studies. As total of 205 articles were obtained after remove duplicates. Finally 7 articles were selected. The main results were that those studies using amateur athletes obtain better results than those performed with professional athletes when performing plyometric training programs. It is also indicated that a period of low intensity plyometric training could prevent a decrease in vertical jump height; As well as it is necessary to schedule the preseason to avoid loss in the ability to jump. All this seems to indicate, in conclusion, that a decrease in volume and an increase in intensity in the training of plyometric training is necessary

Effect of aquatic resistance interval training and dietary education program on physical and psychological health in older women: Randomized controlled trial

Due to demographic changes, the world’s population is progressively aging. The physiological deterioration of the older adult may lead to reduced balance capacity and increased risk of falls, among others, due to the prevalence of degenerative diseases. Physical exercise can be effective in reducing the risk of disease and slowing functional decline in older people. The aim of the research is to test the effects of aquatic resistance training and dietary education on health indicators, strength, balance, functional autonomy, perception of satisfaction with life. Thirty-four participants aged 69 ± 4 years were randomly assigned into two groups: experimental (aquatic resistance interval training) and control group (no intervention). The intervention consisted of resistance training in an aquatic environment carried out for 14 weeks (three sessions per week: 60 min each). All variables were analyzed twice; pre - post intervention. Aquatic resistance training has positive effects on strength (p < 0.001), functional self-sufficiency (p < 0.001) and aerobic capacity (p < 0.001), however, no significant differences were observed in the perception of satisfaction with life and balance. Research results suggest that older women who engage in regular, scheduled aquatic resistance training have greater autonomy in performing activities of daily living, agility, gait control, and body composition variables (lower fat compartment and greater muscle mass)