Percolation-intercropping strategies to prevent dissemination of phytopathogens on plantations.

Phytophthora is one of the most aggressive and worldwide extended phytopathogens that attack plants and trees. Its effects produce tremendous economical losses in agronomy and forestry since no effective fungicide exists. We propose to combine percolation theory with an intercropping sowing configuration as a non-chemical strategy to minimize the dissemination of the pathogen. In this work, we model a plantation as a square lattice where two types of plants are arranged in alternating columns or diagonals, and Phytophthora zoospores are allowed to propagate to the nearest and next-to-nearest neighboring plants. We determine the percolation threshold for each intercropping configuration as a function of the plant's susceptibilities and the number of inoculated cells at the beginning of the propagation process. The results are presented as phase diagrams where crop densities that prevent the formation of a spanning cluster of susceptible or diseased plants are indicated. The main result is the existence of susceptibility value combinations for which no spanning cluster is formed even if every cell in the plantation is sowed. This finding can be useful in choosing a configuration and density of plants that minimize damages caused by Phytophthora. We illustrate the application of the phase diagrams with the susceptibilities of three plants with a high commercial value.

Análisis y modelado de la cultura de seguridad de un hospital mexicano mediante cadenas de Markov / Analysis and modelling of safety culture in a Mexican hospital by Markov chains

Introducción. El objetivo de este estudio fue analizar y modelar la cultura de seguridad con cadenas de Markov, así como predecir o priorizar respecto al tiempo el comportamiento evolutivo de la cultura de seguridad del personal de salud de un hospital mexicano. Método. Se utilizó la teoría de cadenas de Markov. Los datos empleados para el análisis fueron obtenidos de un estudio previo basado en el Cuestionario de Actitudes Seguras (CAS-MX-II), considerando las siguientes 6 dimensiones: clima de seguridad, trabajo en equipo, satisfacción laboral, reconocimiento del nivel de estrés, percepción de la dirección y ambiente de trabajo. Resultados. Entre los hallazgos destacan las predicciones o priorizaciones del tiempo aproximado de posibles arraigos en el comportamiento evolutivo de la cultura de seguridad respecto a clima de seguridad (12 años; 24,1%); trabajo en equipo (8 años; 34,61%); satisfacción laboral (11 años; 52,4%); reconocimiento del nivel de estrés (8 años; 19,35%) y percepción de la dirección (22 años; 27,87%). En la dimensión ambiente de trabajo no fue posible determinar información del comportamiento del personal, es decir, no se obtuvo información de arraigo cultural. Conclusiones. En general, se detectan debilidades en la cultura de seguridad del hospital, lo que constituye una oportunidad para proponer cambios en las políticas mandatorias que permitan su fortalecimiento (AU)

Introduction. The objective of this study was to analyse and model the safety culture with Markov chains, as well as predicting and/or prioritizing over time the evolutionary behaviour of the safety culture of the health's staff in one Mexican hospital. Method. The Markov chain theory has been employed in the analysis, and the input data has been obtained from a previous study based on the Safety Attitude Questionnaire (CAS-MX-II), by considering the following 6 dimensions: safety climate, teamwork, job satisfaction, recognition of stress, perception of management, and work environment. Results. The results highlighted the predictions and/or prioritisation of the approximate time for the possible integration into the evolutionary behaviour of the safety culture as regards the “slightly agree” (Likert scale) for: safety climate (in 12 years; 24.13%); teamwork (8 years; 34.61%); job satisfaction (11 years; 52.41%); recognition of the level of stress (8 years; 19.35%); and perception of the direction (22 years; 27.87%). The work environment dimension was unable to determine the behaviour of staff information, i.e. no information cultural roots were obtained. Conclusion. In general, it has been shown that there are weaknesses in the safety culture of the hospital, which is an opportunity to suggest changes to the mandatory policies in order to strengthen it (AU)

[Analysis and modelling of safety culture in a Mexican hospital by Markov chains]. / Análisis y modelado de la cultura de seguridad de un hospital mexicano mediante cadenas de Markov.

INTRODUCTION: The objective of this study was to analyse and model the safety culture with Markov chains, as well as predicting and/or prioritizing over time the evolutionary behaviour of the safety culture of the health's staff in one Mexican hospital. METHOD: The Markov chain theory has been employed in the analysis, and the input data has been obtained from a previous study based on the Safety Attitude Questionnaire (CAS-MX-II), by considering the following 6 dimensions: safety climate, teamwork, job satisfaction, recognition of stress, perception of management, and work environment. RESULTS: The results highlighted the predictions and/or prioritisation of the approximate time for the possible integration into the evolutionary behaviour of the safety culture as regards the "slightly agree" (Likert scale) for: safety climate (in 12 years; 24.13%); teamwork (8 years; 34.61%); job satisfaction (11 years; 52.41%); recognition of the level of stress (8 years; 19.35%); and perception of the direction (22 years; 27.87%). The work environment dimension was unable to determine the behaviour of staff information, i.e. no information cultural roots were obtained. CONCLUSION: In general, it has been shown that there are weaknesses in the safety culture of the hospital, which is an opportunity to suggest changes to the mandatory policies in order to strengthen it.