Dynamics of a model of Toxoplasmosis disease in human and cat populations

AbstractA mathematical model for the transmission of Toxoplasmosis disease in human and cat populations is proposed and analyzed. We explore the dynamics of the Toxoplasmosis disease at the population level using an epidemiological type model. Discussion of the basic concepts of the Toxoplasmosis transmission dynamics on human and cat populations are presented. The cats in this model plays a role of infectious agents and host of the protozoan Toxoplasma Gondii parasite. Qualitative dynamics of the model is determined by the basic reproduction number, R0. If the threshold parameter R0<1, then the solution converges to the disease free equilibrium point. On the other hand if R0>1 the convergence is to the endemic equilibrium point. Numerical simulations of the model illustrates several different dynamics depending on the threshold parameter R0 and show the importance of this parameter

Maximal oxygen consumption in national elite triathletes that train in high altitude

Triathlon is considered an endurance sport composed by the individual disciplines of swimming, cycling and running which are generally completed in this sequential order. It has been suggested that triathlon performance can be predicted by maximal oxygen uptake (VO2max). However, it has also been suggested that some variables such age, gender, fitness, training and ventilator muscles may affect VO2max. It is the aim of this research to measure and analyze the VO2max of 6 national elite triathletes and one national juvenile triathlete, with long experience, training in a high altitude city (1650m). We compare VO2max for female and male groups. We found differences at the VO2max values for these groups. Additionally, we also found high values of VO2max for these young elite triathletes despite their relative short age, but long sport age

Elite triathlete performance related to age

Triathlon is considered an endurance sport composed by the individual disciplines of swimming, cycling and running. The level of elite triathlon improves every year and the studies of several factors that help to improve the performance of triathletes who compete at Olympic, World Series, European, Pan-American, Commonwealth and others important events are increasing. It has been suggested that triathlon performance decline with age. However, it has also been suggested that experience is an important variable related to performance in sports and especially in crucial events. It is the aim of this research to measure and analyze the correlation between performance and age in international male elite triathletes that have participated in World Cups, Championships Series and World Championships Series from years 2007, 2008, 2009 and 2010. We found that in several cases there is a positive correlation between age and performance. Additionally, we found that the mean age of the top ten finishers in Olympic Games triathlon was higher than in the other triathlons. All these results suggest that experience is important in most relevant international elite triathlon events

Optimization of swimming performance in triathlon

Lette

A Mathematical Model for Social Security Systems with Dynamical Systems

In this paper it is proposed a mathematical approach based on dynamic systems to study the effect of the increase in the Social Security normal retirement age on the worker and on the dynamics of retiree populations. In order to simplify this initial effort, the proposed model does not include some economic variables, such as wage growth, earnings or productivity. Here, we employ numerical simulations of the model to investigate the dynamics of the labor force under different demographic scenarios. Analysis of this type of model with numerical simulations can help government economic planners make optimal strategies to sustain pension systems and forecast future trends of pensioner and worker populations.Este artículo propone una primera aproximación matemática basada en los sistemas dinámicos para estudiar el efecto del aumento de la edad de jubilación de la Seguridad Social de los trabajadores y la dinámica de las poblaciones de jubilados. El modelo propuesto no incluye diversas variables económicas como el crecimiento salarial, los ingresos y la productividad con el fin de obtener un primer enfoque poco complejo. Las simulaciones numéricas del modelo se utilizan para investigar la dinámica de la fuerza de trabajo utilizando diferentes escenarios demográficos. El análisis de este tipo de modelos con simulaciones numéricas puede ayudar a los planificadores económicos de los gobiernos a generar las estrategias óptimas para mantener el sistema de pensiones y obtener pronósticos sobre las poblaciones de pensionistas y trabajadores

Mathematical modeling of Toxoplasmosis disease in varying size populations

AbstractThe prevalence of Toxoplasmosis has increased dramatically around the world. Despite congenital Toxoplasmosis being not a disease of epidemic proportions, a large number of humans die or have serious effects on the developing fetus. In this paper we present an initial model with varying size population for the evolution of the infected people with Toxoplasmosis. We explore the dynamics of the Toxoplasmosis disease at the population level using an epidemiological model. Statistical data are used to estimate some of the parameters of the model. Numerical simulations of the model done by varying parameters show different scenarios about the spread of the disease

Modeling population uncertainty using statistical moments

[EN] In this paper a random differential equation system modeling population dynamics is investigated by means of the statistical moments equation. Monte Carlo simulations are performed in order to compare with the statistical moments equation approach. The randomness in the model appears due to the uncertainty on the initial conditions. The model is a nonlinear differential equation system with random initial conditions and is based on the classical SIS epidemic model. By assuming different probability distribution functions for the initial conditions of different classes of the population we obtain the mean and variance of the stochastic process representing the proportion of these classes at any time. The results show that the theoretical approach of moments equation agrees very well with Monte Carlo numerical results and the solutions converge to the equilibrium point independently of the probability distribution function of the initial conditions.The authors are grateful to the anonymous reviewers for their valuable comments and suggestions which improved the quality and the clarity of the paper. This work has been partially supported by the Spanish M.C.Y.T. and FEDER grants MTM2009–08587, DPI2010–20891–C02–01 as well as the Universitat Polit`ecnica de Val`encia grant PAID-06–09 (ref. 2588).González Parra, GC.; Cortés, J.; Villanueva Micó, RJ.; Santonja, FJ. (2012). Modeling population uncertainty using statistical moments. Boletín de Estadística e Investigación Operativa. 28(3):204-219. http://hdl.handle.net/10251/60564S20421928

Mathematical Modeling and Characterization of the Spread of Chikungunya in Colombia

The Chikungunya virus is the cause of an emerging disease in Asia and Africa, and also in America, where the virus was first detected in 2006. In this paper, we present a mathematical model of the Chikungunya epidemic at the population level that incorporates the transmission vector. The epidemic threshold parameter R 0 for the extinction of disease is computed using the method of the next generation matrix, which allows for insights about what are the most relevant model parameters. Using Lyapunov function theory, some sufficient conditions for global stability of the the disease-free equilibrium are obtained. The proposed mathematical model of the Chikungunya epidemic is used to investigate and understand the importance of some specific model parameters and to give some explanation and understanding about the real infected cases with Chikungunya virus in Colombia for data belonging to the year 2015. In this study, we were able to estimate the value of the basic reproduction number R 0 . We use bootstrapping and Markov chain Monte Carlo techniques in order to study parameters&rsquo; identifiability. Finally, important policies and insights are provided that could help government health institutions in reducing the number of cases of Chikungunya in Colombia

Anales de Edafología y Agrobiología Tomo 43 Número 5-6

Suelos. Estudio de los minerales de la arcilla en unos perfiles de suelos con distintos contenidos en materia organica (Rasgos turbosos), de la Sierra de Guadarrama, por Jiménez Ballesta, R., Martín de Vidales, J. L., Reñones, O. y Gumuzzio, J.-- Distribución de la actividad ureásica en las unidades de estructura del suelo. II. Estado y comportamiento enzimático, por Pérez Mateos, M. y González Carcedo, S.-- Contribución al estudio de los suelos de la Sierra del Pozo (Jaén), por J. González Parra, C. González Huecos y A. López Lafuente.-- Influencia del suelo y métodos de cultivo sobre Longidorus profundorum. Nematodo fitoparasito de interés en las áreas cerealistas de la región central, por M. Fé Andrés y A. Bello.-- Aproximación paramétrica para la evaluación de la aptitud de las tierras, por Gilberto Hernández-Silva, Mariano Vinegas Soto, Mireya Maples Vermeersch y Lourdes Flores Delgadillo.-- Reacción con el FNa de los suelos de Galicia l. Características y significado del test de FNa. Distribución de la reactividad en función del material de partida, por E. García-Rodeja, F. MacÍas y F. Guitian Ojea.-- Naturaleza y propiedades del Humus subacuatico del embalse de Gasset (Ciudad Real), por G. Almendros, A. Polo y E. Dorado.-- Reacción con el FNa de los suelos de Galicia II. Suelos sobre rocas graníticas, por E. García-Rodeja Gayoso, F. Macías Vázquez, F. Guitián Ojea.-- Reacción con el FNa de los suelos de Galicia 111. Suelos formados sobre micaesquistos, pizarras, areniscas y cuarcitas, por E. García-Rodeja Gayoso, Macías Vázquez, F. y Guitián Ojea, F.—Fertilidad del Suelo. Effect o f nitrogen, phosphorus and crude organic matter on the yield and composition of potato and chilli, by K. R. Maurya and N. R. Dhar.-- Efecto de diferentes dosis de fertilización y abonamiento en el contenido y rendimiento de hierro y cobre en Lolium multiflorum lam. var. "Westerwolds", por David Flores-Román, Lourdes Flores-Delgadillo y Nicolás Aguilera-Herrera.-- Criterios para determinar la tolerancia a la salinidad de portainjertos de aguacates. por Díaz, A., Altares, M., Alvarez, C. E. y Fernández, .M.-- Estudio de la asimilabilidad de calcio por plantas de Ryegrass en un suelo tratado con compost urbano, por R. Nogales, F. Gallardo-Lara y M. Gómez.—Nutrición y Fisiología Vegetal. Cultivo de hipocotilos de Digitalis obscura L.: Relación entre morfogénesis y producción de glucosidos cardiotonicos, por M. C. Brisa, P. Pérez-Bermudez y J. Segura.-- Efecto del ácido 2,4-diclorofenoxiacético sobre la inducción de callos en cotiledones de Pinus Canariensis, por Pérez Francés, J. F., C. Martínez y A. C. Blesa.-- Desarrollo de técnicas de cultivo "in vitro" para la micopropagación de variedades de manzana sidrera, por Ricardo Ordas, Ana Rodríguez, Roberto Rodríguez y Ricardo Sánchez Tames.-- Caracterización estadística de limón, por F. A. Melendreras y A. Ortuño.-- Trabajos recapitulativos. Avances recientes en el estudio de las micorrizas V-A. II. Factores que afectan su formación y función y aplicaciones prácticas en agricultura, por C. Azcón-Aguilar, J. M. Barea y B. E. Roldán-Fajardo.-- El tiempo como factor formador del suelo, por M. Delgado Rodríguez y R. Delgado Calvo-Flores.-- Notas.-- BibliografíaPeer reviewe